JP2024127611A - Work Machine - Google Patents

Abstract

[Problem] To improve the accuracy of calculation of the weight of a load. [Solution] A work machine has a lower traveling body, an upper rotating body mounted on the lower traveling body so as to be freely rotatable, an attachment attached to the upper rotating body, and a working tool provided at the tip of the attachment, and while the load is being transported by the working tool, the weight of the load is measured twice at different positions, and if the difference between the two weight measurements is equal to or greater than a predetermined value, a predetermined control is performed to deal with the fall of the load. [Selected Figure] Figure 5

Description

The present invention relates to a work machine.

Conventionally, there has been known a work machine that holds a load on a working tool attached to the tip of an attachment, lifts the load using the attachment, rotates the load so that it is on top of the bed of a dump truck, and then loads the load onto the bed of the dump truck (see, for example, Patent Document 1).

International Publication No. 2019/060109

In recent years, work machines have been equipped with a function to detect the weight of the load. When the weight of the load is detected using this function, if the work machine is transporting a load such as soil or scrap metal, and part of the load is spilled during transport to a dump truck or trailer, etc., this will result in an error in the detection of the weight of the load.

One aspect of the present invention provides a technology that improves the accuracy of calculating the weight of a load being transported by taking into account the possibility that part of the load may spill from the work tool.

A working machine according to one aspect of the present invention has a lower running body, an upper rotating body mounted on the lower running body so as to be freely rotatable, an attachment attached to the upper rotating body, and a working tool provided at the tip of the attachment, and while a load is being transported by the working tool, the weight of the load is measured twice at different positions, and if the difference between the two weight measurements is equal to or greater than a predetermined value, a predetermined control is performed to respond to the fall of the load.

According to one aspect of the present invention, the accuracy of calculating the weight of a load is improved.

FIG. 1 is a side view of a shovel according to a first embodiment. FIG. 2 is a diagram illustrating an example of a configuration of a shovel according to the first embodiment. FIG. 3 is a diagram illustrating an example of a configuration of a hydraulic system of the excavator according to the first embodiment. FIG. 4 is a diagram showing a part of the hydraulic system of the excavator according to the first embodiment. FIG. 5 is a diagram illustrating an example of components related to a weight detection function of the shovel according to the first embodiment. FIG. 6 is a schematic diagram illustrating parameters related to calculation of the weight of a load on the attachment of the shovel according to the first embodiment. FIG. 7 is a diagram showing a movement trajectory of a bucket in the excavator according to the first embodiment until a load is loaded onto a dump truck. FIG. 8 is a flowchart showing a processing procedure up to loading an object by the shovel into the dump truck according to the first embodiment. FIG. 9 is a flowchart showing a processing procedure up to loading an object by a shovel into a dump truck according to the second embodiment. FIG. 10 is a side view of a work machine according to a third embodiment. FIG. 11 is a flow chart showing a processing procedure up to loading of a load by a work machine according to the third embodiment onto a dump truck.

The following describes an embodiment of the present invention with reference to the drawings. The embodiments described below are illustrative and do not limit the invention, and all features and combinations described in the embodiments are not necessarily essential to the invention. In addition, identical or corresponding components in each drawing are denoted by identical or corresponding reference numerals, and descriptions thereof may be omitted.

(Overview of the work machine)
In this embodiment, an example will be described in which a shovel is used as an example of a work machine, but the present invention is not limited to a shovel. The present invention may be applied to a construction machine, a standard machine, an application machine, a forestry machine, or a conveying machine based on a hydraulic shovel.

An overview of the shovel 100 according to this embodiment will be described with reference to FIG. 1. FIG. 1 is a side view of the shovel 100 as a work machine according to this embodiment.

In FIG. 1, the excavator 100 is positioned on a horizontal plane facing the upward slope ES of the construction target, and an upward slope BS (i.e., the slope shape after construction on the upward slope ES), which is an example of the target construction surface described below, is also shown. Note that the upward slope ES of the construction target is provided with a cylinder (not shown) that indicates the normal direction of the upward slope BS, which is the target construction surface.

The excavator 100 according to this embodiment includes a lower carrier 1, an upper rotating body 3 mounted on the lower carrier 1 so as to be freely rotatable via a rotating mechanism 2, a boom 4, an arm 5, and a bucket 6 constituting an attachment (working machine), and a cabin 10.

The lower traveling body 1 allows the excavator 100 to travel by hydraulically driving a pair of left and right crawlers by traveling hydraulic motors 1L, 1R (see FIG. 2 described later). In other words, the pair of traveling hydraulic motors 1L, 1R (an example of a traveling motor) drive the lower traveling body 1 (crawlers) as the driven part.

The upper rotating body 3 is driven by a hydraulic motor 2A (see FIG. 2 described later) to rotate relative to the lower traveling body 1. In other words, the hydraulic motor 2A is a rotation drive unit that drives the upper rotating body 3 as a driven unit, and can change the orientation of the upper rotating body 3.

The upper rotating body 3 may be electrically driven by an electric motor (hereinafter, "swivel electric motor") instead of the swivel hydraulic motor 2A. In other words, the swivel electric motor is a swivel drive unit that drives the upper rotating body 3 as a non-driven unit, similar to the swivel hydraulic motor 2A, and can change the orientation of the upper rotating body 3.

The boom 4 is pivotally attached to the front center of the upper rotating body 3 so that it can be raised and lowered, and an arm 5 is pivotally attached to the tip of the boom 4 so that it can rotate up and down, and a bucket 6 as an end attachment is pivotally attached to the tip of the arm 5 so that it can rotate up and down. The boom 4, arm 5, and bucket 6 are hydraulically driven by a boom cylinder 7, arm cylinder 8, and bucket cylinder 9, which serve as hydraulic actuators, respectively.

The bucket 6 is an example of an end attachment (work tool), and instead of the bucket 6, other end attachments, such as a slope bucket, a dredging bucket, or a breaker, may be attached to the tip of the arm 5 depending on the type of work. Furthermore, a lifting magnet may be attached as an end attachment, and other work tools such as a grapple, demolition fork, or harvester including a chainsaw may be attached depending on the type of work.

The cabin 10 is the driver's cab in which the operator sits and is mounted on the front left side of the upper rotating body 3.

[Excavator configuration]
Next, a specific configuration of the shovel 100 according to this embodiment will be described with reference to FIG. 2 in addition to FIG.

Figure 2 is a diagram showing an example of the configuration of the shovel 100 according to this embodiment.

In Figure 2, the mechanical power system, hydraulic oil lines, pilot lines, and electrical control system are shown by double lines, solid lines, dashed lines, and dotted lines, respectively.

The drive system of the excavator 100 according to this embodiment includes an engine 11, a regulator 13, a main pump 14, and a control valve 17. As described above, the hydraulic drive system of the excavator 100 according to this embodiment includes hydraulic actuators such as the travel hydraulic motors 1L, 1R, the swing hydraulic motor 2A, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 that hydraulically drive the lower travel structure 1, the upper swing structure 3, the boom 4, the arm 5, and the bucket 6, respectively.

The engine 11 is the main power source in the hydraulic drive system, and is mounted, for example, at the rear of the upper rotating body 3. Specifically, the engine 11 rotates at a constant speed at a preset target speed under direct or indirect control by a controller 30 (described later), and drives the main pump 14 and pilot pump 15. The engine 11 is, for example, a diesel engine that uses diesel as fuel.

The regulator 13 controls the discharge volume of the main pump 14. For example, the regulator 13 adjusts the angle (tilt angle) of the swash plate of the main pump 14 in response to a control command from the controller 30. The regulator 13 includes, for example, regulators 13L and 13R, as described below.

The main pump 14 is mounted on the rear of the upper rotating body 3, for example, like the engine 11, and supplies hydraulic oil to the control valve 17 through a high-pressure hydraulic line. The main pump 14 is driven by the engine 11 as described above. The main pump 14 is, for example, a variable displacement hydraulic pump, and as described above, under the control of the controller 30, the tilt angle of the swash plate is adjusted by the regulator 13 to adjust the stroke length of the piston and control the discharge flow rate (discharge pressure). The main pump 14 includes, for example, main pumps 14L and 14R, as described below.

The control valve 17 is a hydraulic control device that controls the hydraulic system in the excavator 100. In this embodiment, the control valve 17 includes control valves 171 to 176. The control valve 175 includes control valve 175L and control valve 175R, and the control valve 176 includes control valve 176L and control valve 176R. The control valve 17 is configured to selectively supply hydraulic oil discharged by the main pump 14 to one or more hydraulic actuators through the control valves 171 to 176. The control valves 171 to 176 control, for example, the flow rate of hydraulic oil flowing from the main pump 14 to the hydraulic actuators and the flow rate of hydraulic oil flowing from the hydraulic actuators to a hydraulic oil tank. The hydraulic actuators include a boom cylinder 7, an arm cylinder 8, a bucket cylinder 9, traveling hydraulic motors 1L and 1R, and a swing hydraulic motor 2A. More specifically, control valve 171 corresponds to left traveling hydraulic motor 1L, control valve 172 corresponds to right traveling hydraulic motor 1R, and control valve 173 corresponds to swing hydraulic motor 2A. Control valve 174 corresponds to bucket cylinder 9, control valve 175 corresponds to boom cylinder 7, and control valve 176 corresponds to arm cylinder 8. Control valve 175 includes control valves 175L and 175R, for example, as described below, and control valve 176 includes control valves 176L and 176R, for example, as described below. Details of control valves 171 to 176 will be described later.

The pilot pump 15 is an example of a pilot pressure generating device, and is configured to supply hydraulic oil to hydraulic control devices via a pilot line. In this embodiment, the pilot pump 15 is a fixed displacement hydraulic pump. However, the pilot pressure generating device may be realized by the main pump 14. That is, the main pump 14 may have a function of supplying hydraulic oil to various hydraulic control devices via a pilot line, in addition to a function of supplying hydraulic oil to the control valve 17 via a hydraulic oil line. In this case, the pilot pump 15 may be omitted.

The operating device 26 is a device that an operator uses to operate the actuator. The actuator includes at least one of a hydraulic actuator and an electric actuator.

The discharge pressure sensor 28 is configured to detect the discharge pressure of the main pump 14. In this embodiment, the discharge pressure sensor 28 outputs the detected value to the controller 30. The discharge pressure sensor 28 includes, for example, discharge pressure sensors 28L and 28R, as described below.

The operation sensor 29 is configured to detect the operation content of the operator using the operation device 26. In this embodiment, the operation sensor 29 detects the operation direction and operation amount of the operation device 26 corresponding to each actuator, and outputs the detected value to the controller 30. In this embodiment, the controller 30 controls the opening area of the proportional valve 31 according to the output of the operation sensor 29. Then, the controller 30 supplies the hydraulic oil discharged by the pilot pump 15 to the pilot port of the corresponding control valve in the control valve 17. The pressure of the hydraulic oil (pilot pressure) supplied to each pilot port is, in principle, a pressure according to the operation direction and operation amount of the operation device 26 corresponding to each hydraulic actuator. In this way, the operation device 26 is configured to be able to supply the hydraulic oil discharged by the pilot pump 15 to the pilot port of the corresponding control valve in the control valve 17.

The proportional valve 31, which functions as a control valve for machine control, is disposed in a pipe connecting the pilot pump 15 and the pilot port of the control valve in the control valve 17, and is configured so that the flow area of the pipe can be changed. In this embodiment, the proportional valve 31 operates in response to a control command output by the controller 30. Therefore, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the pilot port of the control valve in the control valve 17 via the proportional valve 31, regardless of the operation of the operating device 26 by the operator. The proportional valve 31 includes, for example, proportional valves 31AL, 31AR, 31BL, 31BR, 31CL, and 31CR, as described below.

With this configuration, the controller 30 can operate the hydraulic actuator corresponding to a specific operating device 26 even when no operation is being performed on that specific operating device 26.

The control system of the excavator 100 according to this embodiment includes a controller 30, a display device 40, an input device 42, an audio output device 43, a storage device 47, a boom angle sensor S1, an arm angle sensor S2, a bucket angle sensor S3, a machine body inclination sensor S4, a turning state sensor S5, an imaging device S6, a positioning device PS, and a communication device T1.

The controller 30 (an example of a control device) is provided, for example, in the cabin 10 and controls the drive of the excavator 100. The functions of the controller 30 may be realized by any hardware, software, or a combination thereof. For example, the controller 30 is configured mainly with a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a non-volatile auxiliary storage device, and various input/output interfaces. The controller 30 realizes various functions by, for example, executing various programs stored in the ROM or non-volatile auxiliary storage device on the CPU.

For example, the controller 30 sets a target rotation speed based on a work mode that is preset by a specific operation by an operator or the like, and performs drive control to rotate the engine 11 at a constant speed.

For example, the controller 30 also outputs a control command to the regulator 13 as necessary to change the discharge rate of the main pump 14.

For example, the controller 30 also controls a machine guidance function that guides the operator in manually operating the shovel 100 through the operating device 26. For example, the controller 30 also controls a machine control function that automatically assists the operator in manually operating the shovel 100 through the operating device 26. That is, the controller 30 includes a machine guidance unit 50 as a functional unit related to the machine guidance function and the machine control function. The controller 30 also includes a weight processing unit 60, which will be described later.

Note that some of the functions of the controller 30 may be realized by other controllers (control devices). That is, the functions of the controller 30 may be realized in a distributed manner by multiple controllers. For example, the machine guidance function and the machine control function may be realized by a dedicated controller (control device).

The display device 40 is provided in a location that is easily visible to an operator seated in the cabin 10, and displays various information images under the control of the controller 30. The display device 40 may be connected to the controller 30 via an in-vehicle communication network such as a Controller Area Network (CAN), or may be connected to the controller 30 via a one-to-one dedicated line.

The input device 42 is provided within reach of an operator seated in the cabin 10, accepts various operational inputs by the operator, and outputs signals corresponding to the operational inputs to the controller 30. The input device 42 includes a touch panel mounted on the display of a display device that displays various information images, knob switches provided at the tips of the lever portions of the lever devices 26A to 26C, button switches, levers, toggles, rotary dials, etc., that are installed around the display device 40. Signals corresponding to the operations performed on the input device 42 are input to the controller 30.

The audio output device 43 is provided, for example, in the cabin 10, connected to the controller 30, and outputs audio under the control of the controller 30. The audio output device 43 is, for example, a speaker or a buzzer. The audio output device 43 outputs various information by audio in response to an audio output command from the controller 30.

The storage device 47 is provided, for example, in the cabin 10, and stores various information under the control of the controller 30. The storage device 47 is, for example, a non-volatile storage medium such as a semiconductor memory. The storage device 47 may store information output by various devices during operation of the shovel 100, or may store information acquired via various devices before operation of the shovel 100 is started. The storage device 47 may store data regarding a target construction surface acquired, for example, via a communication device T1, or set via an input device 42, or the like. The target construction surface may be set (saved) by the operator of the shovel 100, or may be set by a construction manager, or the like.

The boom angle sensor S1 is attached to the boom 4 and detects the elevation angle of the boom 4 relative to the upper rotating body 3 (hereinafter referred to as the "boom angle"), for example, the angle formed by a straight line connecting the fulcrums at both ends of the boom 4 relative to the rotation plane of the upper rotating body 3 in a side view. The boom angle sensor S1 may include, for example, a rotary encoder, an acceleration sensor, a six-axis sensor, an IMU (Inertial Measurement Unit), etc. The boom angle sensor S1 may also include a potentiometer using a variable resistor, a cylinder stroke sensor that detects the stroke amount of a hydraulic cylinder (boom cylinder 7) corresponding to the boom angle, etc. The same applies to the arm angle sensor S2 and bucket angle sensor S3 below. The detection signal corresponding to the boom angle by the boom angle sensor S1 is taken into the controller 30.

The arm angle sensor S2 is attached to the arm 5 and detects the rotation angle of the arm 5 relative to the boom 4 (hereinafter, "arm angle"), for example, the angle formed by a line connecting the fulcrums at both ends of the arm 5 with a line connecting the fulcrums at both ends of the boom 4 in a side view. A detection signal corresponding to the arm angle by the arm angle sensor S2 is input to the controller 30.

The bucket angle sensor S3 is attached to the bucket 6 and detects the rotation angle of the bucket 6 relative to the arm 5 (hereinafter, the "bucket angle"), for example, the angle formed by a line connecting the fulcrums at both ends of the arm 5 and a line connecting the fulcrum and tip (tip) of the bucket 6 in a side view. A detection signal corresponding to the bucket angle by the bucket angle sensor S3 is input to the controller 30.

The machine body tilt sensor S4 detects the tilt state of the machine body (upper rotating body 3 or lower running body 1) relative to the horizontal plane. The machine body tilt sensor S4 is attached, for example, to the upper rotating body 3, and detects the tilt angles around two axes in the forward/backward and left/right directions (hereinafter, "forward/rearward tilt angle" and "left/right tilt angle") of the shovel 100 (i.e., upper rotating body 3). The machine body tilt sensor S4 may include, for example, a rotary encoder, an acceleration sensor, a six-axis sensor, an IMU, etc. The detection signal corresponding to the tilt angle (forward/backward tilt angle and left/right tilt angle) by the machine body tilt sensor S4 is input to the controller 30.

The rotation state sensor S5 outputs detection information regarding the rotation state of the upper rotating body 3. The rotation state sensor S5 detects, for example, the rotation angular velocity and rotation angle of the upper rotating body 3. The rotation state sensor S5 may include, for example, a gyro sensor, a resolver, a rotary encoder, etc. The detection signal corresponding to the rotation angle and rotation angular velocity of the upper rotating body 3 by the rotation state sensor S5 is input to the controller 30.

The imaging device S6, which serves as a spatial recognition device, captures images of the periphery of the shovel 100. The imaging device S6 includes a camera S6F that captures an image in front of the shovel 100, a camera S6L that captures an image to the left of the shovel 100, a camera S6R that captures an image to the right of the shovel 100, and a camera S6B that captures an image behind the shovel 100.

Camera S6F is attached, for example, to the ceiling of cabin 10, i.e., inside cabin 10. Camera S6F may also be attached to the outside of cabin 10, such as the roof of cabin 10 or the side of boom 4. Camera S6L is attached to the left end of the top surface of upper rotating body 3, camera S6R is attached to the right end of the top surface of upper rotating body 3, and camera S6B is attached to the rear end of the top surface of upper rotating body 3.

Each of the imaging device S6 (cameras S6F, S6B, S6L, and S6R) is, for example, a monocular wide-angle camera with a very wide angle of view. The imaging device S6 may also be a stereo camera or a distance imaging camera. Images captured by the imaging device S6 are input to the controller 30 via the display device 40.

The imaging device S6 as a spatial recognition device may function as an object detection device. In this case, the imaging device S6 may detect an object present around the shovel 100. The object to be detected may include, for example, a person, an animal, a vehicle, a construction machine, a building, a hole, etc. The imaging device S6 may also calculate the distance from the imaging device S6 or the shovel 100 to the recognized object. The imaging device S6 as an object detection device may include, for example, a stereo camera, a distance image sensor, etc. The spatial recognition device is, for example, a monocular camera having an imaging element such as a CCD or a CMOS, and outputs the captured image to the display device 40. The spatial recognition device may also be configured to calculate the distance from the spatial recognition device or the shovel 100 to the recognized object. In addition to the imaging device S6, other object detection devices such as an ultrasonic sensor, a millimeter wave radar, a LIDAR, an infrared sensor, etc. may be provided as the spatial recognition device. When using a millimeter wave radar, ultrasonic sensor, laser radar, or the like as a spatial recognition device, multiple signals (laser light, etc.) can be emitted to an object, and the reflected signals can be received to detect the distance and direction of the object from the reflected signals.

The imaging device S6 may also be directly connected to the controller 30 so as to be able to communicate with it.

A boom rod pressure sensor S7R and a boom bottom pressure sensor S7B are attached to the boom cylinder 7. An arm rod pressure sensor S8R and an arm bottom pressure sensor S8B are attached to the arm cylinder 8. A bucket rod pressure sensor S9R and a bucket bottom pressure sensor S9B are attached to the bucket cylinder 9. The boom rod pressure sensor S7R, the boom bottom pressure sensor S7B, the arm rod pressure sensor S8R, the arm bottom pressure sensor S8B, the bucket rod pressure sensor S9R and the bucket bottom pressure sensor S9B are collectively referred to as the "cylinder pressure sensors."

The boom rod pressure sensor S7R detects the pressure in the rod side oil chamber of the boom cylinder 7 (hereinafter referred to as the "boom rod pressure"), and the boom bottom pressure sensor S7B detects the pressure in the bottom side oil chamber of the boom cylinder 7 (hereinafter referred to as the "boom bottom pressure"). The arm rod pressure sensor S8R detects the pressure in the rod side oil chamber of the arm cylinder 8 (hereinafter referred to as the "arm rod pressure"), and the arm bottom pressure sensor S8B detects the pressure in the bottom side oil chamber of the arm cylinder 8 (hereinafter referred to as the "arm bottom pressure"). The bucket rod pressure sensor S9R detects the pressure in the rod side oil chamber of the bucket cylinder 9 (hereinafter referred to as the "bucket rod pressure"), and the bucket bottom pressure sensor S9B detects the pressure in the bottom side oil chamber of the bucket cylinder 9 (hereinafter referred to as the "bucket bottom pressure").

The positioning device PS measures the position and orientation of the upper rotating body 3. The positioning device PS is, for example, a Global Navigation Satellite System (GNSS) compass, which detects the position and orientation of the upper rotating body 3, and a detection signal corresponding to the position and orientation of the upper rotating body 3 is input to the controller 30. In addition, the function of the positioning device PS to detect the orientation of the upper rotating body 3 may be replaced by a direction sensor attached to the upper rotating body 3.

The communication device T1 communicates with external devices through a predetermined network including a mobile communication network with a base station as an end, a satellite communication network, the Internet, etc. The communication device T1 is, for example, a mobile communication module compatible with mobile communication standards such as LTE (Long Term Evolution), 4G ( ^4th Generation), and 5G ( ^5th Generation), or a satellite communication module for connecting to a satellite communication network.

The machine guidance unit 50, for example, executes control of the excavator 100 regarding the machine guidance function. The machine guidance unit 50 conveys work information, such as the distance between the target construction surface and the tip of the attachment, specifically, the working part of the end attachment, to the operator through the display device 40, the audio output device 43, etc. Data regarding the target construction surface is, for example, stored in advance in the storage device 47 as described above. Data regarding the target construction surface is, for example, expressed in a reference coordinate system. The reference coordinate system is, for example, the World Geodetic System. The World Geodetic System is a three-dimensional orthogonal XYZ coordinate system with the origin at the center of gravity of the earth, the X axis in the direction of the intersection of the Greenwich meridian and the equator, the Y axis in the direction of 90 degrees east longitude, and the Z axis in the direction of the North Pole. The operator may set any point on the construction site as a reference point and set the target construction surface through the input device 42 based on the relative positional relationship with the reference point. The working part of the bucket 6 is, for example, the tip of the bucket 6, the back of the bucket 6, etc. Also, if, for example, a breaker is used as the end attachment instead of the bucket 6, the tip of the breaker corresponds to the working part. The machine guidance unit 50 notifies the operator of work information via the display device 40, the audio output device 43, etc., and guides the operator in operating the excavator 100 via the operating device 26.

The machine guidance unit 50 also controls the excavator 100, for example, with respect to the machine control function. For example, when an operator is manually performing an excavation operation, the machine guidance unit 50 may automatically operate at least one of the boom 4, the arm 5, and the bucket 6 so that the target construction surface and the tip position of the bucket 6 coincide with each other.

The machine guidance unit 50 acquires information from the boom angle sensor S1, arm angle sensor S2, bucket angle sensor S3, vehicle tilt sensor S4, turning state sensor S5, imaging device S6, positioning device PS, communication device T1, input device 42, etc. Then, the machine guidance unit 50 calculates the distance between the bucket 6 and the target construction surface based on the acquired information, notifies the operator of the degree of the distance between the bucket 6 and the target construction surface by the sound from the sound output device 43 and the image displayed on the display device 40, and automatically controls the operation of the attachment so that the tip of the attachment (specifically, the working part such as the tip or back of the bucket 6) coincides with the target construction surface. The machine guidance unit 50 includes a position calculation unit 51, a distance calculation unit 52, an information transmission unit 53, an automatic control unit 54, a turning angle calculation unit 55, and a relative angle calculation unit 56 as detailed functional configurations related to the machine guidance function and the machine control function.

The position calculation unit 51 calculates the position of a predetermined positioning target. For example, the position calculation unit 51 calculates the coordinate point in a reference coordinate system of the tip of the attachment, specifically, the working part such as the tip or back of the bucket 6. Specifically, the position calculation unit 51 calculates the coordinate point of the working part of the bucket 6 from the respective elevation and depression angles (boom angle, arm angle, and bucket angle) of the boom 4, arm 5, and bucket 6.

The distance calculation unit 52 calculates the distance between two positioning targets. For example, the distance calculation unit 52 calculates the distance between the tip of the attachment, specifically, the working part such as the tip or back of the bucket 6, and the target construction surface. The distance calculation unit 52 may also calculate the angle (relative angle) between the back of the bucket 6 as the working part and the target construction surface.

The information transmission unit 53 transmits (notifies) various information to the operator of the shovel 100 through a predetermined notification means such as the display device 40 or the audio output device 43. The information transmission unit 53 notifies the operator of the shovel 100 of the magnitude (degree) of various distances calculated by the distance calculation unit 52. For example, the information transmission unit 53 notifies the operator of the distance (magnitude) between the tip of the bucket 6 and the target construction surface using at least one of visual information from the display device 40 and audio information from the audio output device 43. The information transmission unit 53 may also notify the operator of the relative angle (magnitude) between the back of the bucket 6 as the working part and the target construction surface using at least one of visual information from the display device 40 and audio information from the audio output device 43.

Specifically, the information transmission unit 53 uses intermittent sounds from the audio output device 43 to inform the operator of the distance (e.g., vertical distance) between the working part of the bucket 6 and the target construction surface. In this case, the information transmission unit 53 may shorten the interval of the intermittent sounds as the vertical distance decreases, and may lengthen the interval of the intermittent sounds as the vertical distance increases. The information transmission unit 53 may also use a continuous sound, or may express differences in the vertical distance by varying the pitch, strength, etc. of the sound. The information transmission unit 53 may also issue an alarm through the audio output device 43 when the tip of the bucket 6 is lower than the target construction surface, that is, when it has passed the target construction surface. The alarm is, for example, a continuous sound that is significantly louder than the intermittent sound.

The information transmission unit 53 may also cause the display device 40 to display, as work information, the distance between the tip of the attachment, specifically the working part of the bucket 6, and the target construction surface, and the relative angle between the back surface of the bucket 6 and the target construction surface. Under the control of the controller 30, the display device 40 displays the work information received from the information transmission unit 53 together with, for example, image data received from the imaging device S6. The information transmission unit 53 may convey the vertical distance to the operator using, for example, an image of an analog meter or an image of a bar graph indicator.

Furthermore, the information transmission unit 53 transmits (notifies) information regarding the processing results by the weight processing unit 60 described below to the operator of the excavator 100. For example, when the processing by the weight processing unit 60 determines that part of the load (e.g., soil) has spilled from the bucket 6, the information transmission unit 53 notifies the operator of information indicating that part of the load has spilled.

The automatic control unit 54 automatically assists the operator in manually operating the excavator 100 through the operation device 26 by automatically operating the actuators. Specifically, the automatic control unit 54 can individually and automatically adjust the pilot pressure acting on the control valves (specifically, the control valve 173, the control valves 175L, 175R, and the control valve 174) corresponding to the multiple hydraulic actuators (specifically, the swing hydraulic motor 2A, the boom cylinder 7, and the bucket cylinder 9), as described below. This allows the automatic control unit 54 to automatically operate each hydraulic actuator. The control of the machine control function by the automatic control unit 54 may be performed, for example, when a predetermined switch included in the input device 42 is pressed. The predetermined switch may be, for example, a machine control switch (hereinafter, "MC (Machine Control) switch"), and may be disposed as a knob switch at the tip of the operator's grip of the operation device 26 (for example, a lever device corresponding to the operation of the arm 5). The following description will be given on the assumption that the machine control function is active when the MC switch is pressed.

For example, when an MC switch or the like is pressed, the automatic control unit 54 automatically extends and retracts at least one of the boom cylinder 7 and the bucket cylinder 9 in accordance with the operation of the arm cylinder 8 to support excavation and shaping work. Specifically, when an operator manually performs a closing operation of the arm 5 (hereinafter, "arm closing operation"), the automatic control unit 54 automatically extends and retracts at least one of the boom cylinder 7 and the bucket cylinder 9 so that the target construction surface coincides with the position of a work part such as the tip or back of the bucket 6. In this case, the operator can close the arm 5 while aligning the tip of the bucket 6 with the target construction surface, simply by performing an arm closing operation on a lever device corresponding to the operation of the arm 5, for example.

When an MC switch or the like is pressed, the automatic control unit 54 may automatically rotate the rotation hydraulic motor 2A (an example of an actuator) to face the upper rotating body 3 to the target construction surface. Hereinafter, the control by the controller 30 (automatic control unit 54) to face the upper rotating body 3 to the target construction surface is referred to as "facing control." This allows an operator or the like to face the upper rotating body 3 to the target construction surface simply by pressing a specified switch, or, with the switch pressed, by operating a lever device 26C (described below) corresponding to the turning operation. Also, by simply pressing an MC switch, the operator can face the upper rotating body 3 to the target construction surface and start the machine control function related to the excavation work on the target construction surface described above.

For example, when the upper rotating body 3 of the shovel 100 faces the target construction surface, the tip of the attachment (e.g., the tip or back of the bucket 6 as the working part) can be moved along the inclination direction of the target construction surface (upward slope BS) in accordance with the operation of the attachment. Specifically, when the upper rotating body 3 of the shovel 100 faces the target construction surface, the working surface of the attachment (attachment working surface) perpendicular to the rotation plane of the shovel 100 includes the normal to the target construction surface corresponding to the cylinder (in other words, it is along the normal).

If the working surface of the attachment of the shovel 100 does not include the normal to the target construction surface corresponding to the cylinder, the tip of the attachment cannot move the target construction surface in the inclined direction. As a result, the shovel 100 cannot properly construct the target construction surface. In response to this, the automatic control unit 54 can automatically rotate the turning hydraulic motor 2A to orient the upper turning body 3 directly. This allows the shovel 100 to properly construct the target construction surface.

In the facing control, the automatic control unit 54 determines that the shovel is facing the target construction surface, for example, when the left end vertical distance between the coordinate point of the left end of the tip of the bucket 6 and the target construction surface (hereinafter simply referred to as the "left end vertical distance") and the right end vertical distance between the coordinate point of the right end of the tip of the bucket 6 and the target construction surface (hereinafter simply referred to as the "right end vertical distance") are equal. In addition, the automatic control unit 54 may determine that the shovel 100 is facing the target construction surface not when the left end vertical distance and the right end vertical distance are equal (i.e., when the difference between the left end vertical distance and the right end vertical distance becomes zero), but when the difference becomes equal to or less than a predetermined threshold value.

In addition, the automatic control unit 54 may operate the swing hydraulic motor 2A in the facing control, for example, based on the difference between the left end vertical distance and the right end vertical distance. Specifically, when the lever device 26C corresponding to the swing operation is operated with a predetermined switch such as an MC switch pressed, the automatic control unit 54 determines whether the lever device 26C is operated in a direction to face the upper swing body 3 to the target construction surface. For example, if the lever device 26C is operated in a direction to increase the vertical distance between the tip of the bucket 6 and the target construction surface (upward slope BS), the automatic control unit 54 does not execute the facing control. On the other hand, if the swing operation lever is operated in a direction to decrease the vertical distance between the tip of the bucket 6 and the target construction surface (upward slope BS), the automatic control unit 54 executes the facing control. As a result, the automatic control unit 54 can operate the swing hydraulic motor 2A so that the difference between the left end vertical distance and the right end vertical distance is reduced. Thereafter, when the difference becomes equal to or less than a predetermined threshold or becomes zero, the automatic control unit 54 stops the swing hydraulic motor 2A. The automatic control unit 54 may also set the swing angle at which the difference becomes equal to or less than a predetermined threshold or becomes zero as a target angle, and control the operation of the swing hydraulic motor 2A so that the angle difference between the target angle and the current swing angle (specifically, the detection value based on the detection signal of the swing state sensor S5) becomes zero. In this case, the swing angle is, for example, the angle of the front and rear axes of the upper swing body 3 relative to the reference direction.

As described above, when a turning electric motor is installed on the excavator 100 instead of the turning hydraulic motor 2A, the automatic control unit 54 performs facing control with the turning electric motor (an example of an actuator) as the control target.

The slewing angle calculation unit 55 calculates the slewing angle of the upper rotating body 3. This allows the controller 30 to identify the current orientation of the upper rotating body 3. The slewing angle calculation unit 55 calculates the angle of the front-rear axis of the upper rotating body 3 relative to a reference direction as the slewing angle, for example, based on the output signal of the GNSS compass included in the positioning device PS. The slewing angle calculation unit 55 may also calculate the slewing angle based on the detection signal of the slewing state sensor S5. Furthermore, if a reference point is set at the construction site, the slewing angle calculation unit 55 may use the direction of the reference point as viewed from the slewing axis as the reference direction.

The rotation angle indicates the direction in which the attachment working surface extends relative to the reference direction. The attachment working surface is, for example, a virtual plane that cuts the attachment longitudinally and is positioned so as to be perpendicular to the rotation plane. The rotation plane is, for example, a virtual plane that includes the bottom surface of the rotating frame that is perpendicular to the rotation axis. The controller 30 (machine guidance unit 50) determines that the upper rotating body 3 is directly facing the target construction surface when it determines, for example, that the attachment working surface includes the normal to the target construction surface.

The relative angle calculation unit 56 calculates the rotation angle (relative angle) required to make the upper rotating body 3 face the target construction surface. The relative angle is, for example, the relative angle formed between the direction of the front-rear axis of the upper rotating body 3 when the upper rotating body 3 is faced directly to the target construction surface and the current direction of the front-rear axis of the upper rotating body 3. The relative angle calculation unit 56 calculates the relative angle based on, for example, data related to the target construction surface stored in the storage device 47 and the rotation angle calculated by the rotation angle calculation unit 55.

When the lever device 26C corresponding to the rotation operation is operated with a predetermined switch such as an MC switch pressed, the automatic control unit 54 determines whether the upper rotating body 3 has been rotated in a direction to face the target construction surface. If the automatic control unit 54 determines that the upper rotating body 3 has been rotated in a direction to face the target construction surface, it sets the relative angle calculated by the relative angle calculation unit 56 as the target angle. Then, if the change in the rotation angle after the lever device 26C is operated reaches the target angle, the automatic control unit 54 may determine that the upper rotating body 3 faces the target construction surface and stop the movement of the rotation hydraulic motor 2A. As a result, the automatic control unit 54 can make the upper rotating body 3 face the target construction surface, assuming the configuration shown in FIG. 2. In the above embodiment of the facing control, an example of the facing control to the target construction surface is shown, but this is not limited to this. For example, even in the scooping operation when loading temporary soil and sand onto a dump truck, a target excavation trajectory corresponding to the target volume may be generated, and the turning operation may be controlled so that the attachment faces the target excavation trajectory. In this case, the target excavation trajectory is changed each time a scooping operation is performed. Therefore, after discharging the soil and sand onto the dump truck, the attachment is controlled to face the newly changed target excavation trajectory.

[Excavator hydraulic system]
Next, the hydraulic system of the excavator 100 according to this embodiment will be described with reference to FIG.

Figure 3 is a diagram showing an example of the configuration of a hydraulic system of the excavator 100 according to this embodiment.

In Figure 3, the mechanical power system, hydraulic oil lines, pilot lines, and electrical control system are shown by double lines, solid lines, dashed lines, and dotted lines, respectively, as in Figure 2, etc.

The hydraulic system realized by this hydraulic circuit circulates hydraulic oil from each of the main pumps 14L, 14R driven by the engine 11 through the center bypass oil passages C1L, C1R and the parallel oil passages C2L, C2R to the hydraulic oil tank.

The center bypass oil passage C1L starts at the main pump 14L, passes through the control valves 171, 173, 175L, and 176L arranged in the control valve 17, and reaches the hydraulic oil tank.

The center bypass oil passage C1R starts at the main pump 14R, passes through the control valves 172, 174, 175R, and 176R arranged in the control valve 17, and reaches the hydraulic oil tank.

The control valve 171 is a spool valve that supplies hydraulic oil discharged from the main pump 14L to the travel hydraulic motor 1L and discharges hydraulic oil discharged by the travel hydraulic motor 1L into the hydraulic oil tank.

The control valve 172 is a spool valve that supplies hydraulic oil discharged from the main pump 14R to the traveling hydraulic motor 1R and discharges hydraulic oil discharged by the traveling hydraulic motor 1R into the hydraulic oil tank.

The control valve 173 is a spool valve that supplies hydraulic oil discharged from the main pump 14L to the swing hydraulic motor 2A and discharges hydraulic oil discharged by the swing hydraulic motor 2A into the hydraulic oil tank.

The control valve 174 is a spool valve that supplies hydraulic oil discharged from the main pump 14R to the bucket cylinder 9 and also discharges the hydraulic oil in the bucket cylinder 9 to the hydraulic oil tank.

The control valves 175L and 175R are spool valves that supply hydraulic oil discharged from the main pumps 14L and 14R to the boom cylinder 7 and discharge the hydraulic oil in the boom cylinder 7 to the hydraulic oil tank.

The control valves 176L, 176R supply hydraulic oil discharged by the main pumps 14L, 14R to the arm cylinder 8, and also discharge the hydraulic oil in the arm cylinder 8 to the hydraulic oil tank.

Control valves 171, 172, 173, 174, 175L, 175R, 176L, and 176R each adjust the flow rate of hydraulic oil supplied to or discharged from the hydraulic actuator and switch the flow direction according to the pilot pressure acting on the pilot port.

The parallel oil passage C2L supplies hydraulic oil of the main pump 14L to the control valves 171, 173, 175L, and 176L in parallel with the center bypass oil passage C1L. Specifically, the parallel oil passage C2L branches off from the center bypass oil passage C1L upstream of the control valve 171, and is configured to be able to supply hydraulic oil of the main pump 14L in parallel to each of the control valves 171, 173, 175L, and 176R. This allows the parallel oil passage C2L to supply hydraulic oil to a more downstream control valve when the flow of hydraulic oil through the center bypass oil passage C1L is restricted or blocked by any of the control valves 171, 173, and 175L.

The parallel oil passage C2R supplies hydraulic oil of the main pump 14R to the control valves 172, 174, 175R, and 176R in parallel with the center bypass oil passage C1R. Specifically, the parallel oil passage C2R branches off from the center bypass oil passage C1R upstream of the control valve 172, and is configured to be able to supply hydraulic oil of the main pump 14R in parallel to each of the control valves 172, 174, 175R, and 176R. The parallel oil passage C2R can supply hydraulic oil to a more downstream control valve when the flow of hydraulic oil through the center bypass oil passage C1R is restricted or blocked by any of the control valves 172, 174, and 175R.

Regulators 13L and 13R adjust the discharge volume of main pumps 14L and 14R by adjusting the tilt angle of the swash plates of main pumps 14L and 14R, respectively, under the control of controller 30.

The discharge pressure sensor 28L detects the discharge pressure of the main pump 14L, and a detection signal corresponding to the detected discharge pressure is input to the controller 30. The same is true for the discharge pressure sensor 28R. This allows the controller 30 to control the regulators 13L, 13R according to the discharge pressures of the main pumps 14L, 14R.

Negative control throttles (hereinafter "negative control throttles") 18L, 18R are provided in the center bypass oil passages C1L, C1R between the hydraulic oil tank and the most downstream control valves 176L, 176R, respectively. As a result, the flow of hydraulic oil discharged by the main pumps 14L, 14R is restricted by the negative control throttles 18L, 18R. The negative control throttles 18L, 18R then generate a control pressure (hereinafter "negative control pressure") for controlling the regulators 13L, 13R.

The negative control pressure sensors 19L and 19R detect the negative control pressure, and the detection signal corresponding to the detected negative control pressure is input to the controller 30.

The controller 30 may control the regulators 13L, 13R in response to the discharge pressure of the main pumps 14L, 14R detected by the discharge pressure sensors 28L, 28R to adjust the discharge volume of the main pumps 14L, 14R. For example, the controller 30 may control the regulator 13L in response to an increase in the discharge pressure of the main pump 14L, and reduce the discharge volume by adjusting the swash plate tilt angle of the main pump 14L. The same applies to the regulator 13R. This allows the controller 30 to control the total horsepower of the main pumps 14L, 14R so that the absorption horsepower of the main pumps 14L, 14R, which is expressed as the product of the discharge pressure and the discharge volume, does not exceed the output horsepower of the engine 11.

The controller 30 may also adjust the discharge volume of the main pumps 14L, 14R by controlling the regulators 13L, 13R according to the negative control pressure detected by the negative control pressure sensors 19L, 19R. For example, the controller 30 decreases the discharge volume of the main pumps 14L, 14R as the negative control pressure increases, and increases the discharge volume of the main pumps 14L, 14R as the negative control pressure decreases.

Specifically, when the excavator 100 is in a standby state (state shown in FIG. 3) in which none of the hydraulic actuators are being operated, the hydraulic oil discharged from the main pumps 14L, 14R passes through the center bypass oil passages C1L, C1R to reach the negative control throttles 18L, 18R. The flow of hydraulic oil discharged from the main pumps 14L, 14R increases the negative control pressure generated upstream of the negative control throttles 18L, 18R. As a result, the controller 30 reduces the discharge rate of the main pumps 14L, 14R to the minimum allowable discharge rate, suppressing the pressure loss (pumping loss) that occurs when the discharged hydraulic oil passes through the center bypass oil passages C1L, C1R.

On the other hand, when any of the hydraulic actuators is operated through the operating device 26, the hydraulic oil discharged from the main pumps 14L, 14R flows into the hydraulic actuator to be operated through the control valve corresponding to the hydraulic actuator to be operated. The flow of hydraulic oil discharged from the main pumps 14L, 14R reduces or eliminates the amount of hydraulic oil reaching the negative control throttles 18L, 18R, lowering the negative control pressure generated upstream of the negative control throttles 18L, 18R. As a result, the controller 30 increases the discharge amount of the main pumps 14L, 14R, circulates sufficient hydraulic oil to the hydraulic actuator to be operated, and can reliably drive the hydraulic actuator to be operated.

The operating device 26 includes a left operating lever 26L, a right operating lever 26R, and a driving lever 26D. The driving lever 26D includes a left driving lever 26DL and a right driving lever 26DR.

The left operating lever 26L is used for rotation operation and operation of the arm 5. When the left operating lever 26L is operated in the forward/backward direction, the hydraulic oil discharged by the pilot pump 15 is used to introduce a control pressure according to the amount of lever operation into the pilot port of the control valve 176. When the left operating lever 26L is operated in the left/right direction, the hydraulic oil discharged by the pilot pump 15 is used to introduce a control pressure according to the amount of lever operation into the pilot port of the control valve 173.

Specifically, when the left operating lever 26L is operated in the arm closing direction, it introduces hydraulic oil to the right pilot port of the control valve 176L and introduces hydraulic oil to the left pilot port of the control valve 176R. When the left operating lever 26L is operated in the arm opening direction, it introduces hydraulic oil to the left pilot port of the control valve 176L and introduces hydraulic oil to the right pilot port of the control valve 176R. When the left operating lever 26L is operated in the left turning direction, it introduces hydraulic oil to the left pilot port of the control valve 173, and when operated in the right turning direction, it introduces hydraulic oil to the right pilot port of the control valve 173.

The right operating lever 26R is used to operate the boom 4 and the bucket 6. When the right operating lever 26R is operated in the forward/backward direction, it uses the hydraulic oil discharged by the pilot pump 15 to introduce a control pressure according to the amount of lever operation into the pilot port of the control valve 175. When the right operating lever 26R is operated in the left/right direction, it uses the hydraulic oil discharged by the pilot pump 15 to introduce a control pressure according to the amount of lever operation into the pilot port of the control valve 174.

Specifically, when the right operating lever 26R is operated in the boom lowering direction, it introduces hydraulic oil to the left pilot port of the control valve 175R. When the right operating lever 26R is operated in the boom raising direction, it introduces hydraulic oil to the right pilot port of the control valve 175L and also introduces hydraulic oil to the left pilot port of the control valve 175R. When the right operating lever 26R is operated in the bucket closing direction, it introduces hydraulic oil to the right pilot port of the control valve 174, and when the right operating lever 26R is operated in the bucket opening direction, it introduces hydraulic oil to the left pilot port of the control valve 174.

In the following, the left operating lever 26L operated in the left-right direction may be referred to as the "swing operating lever," and the left operating lever 26L operated in the front-rear direction may be referred to as the "arm operating lever." In addition, the right operating lever 26R operated in the left-right direction may be referred to as the "bucket operating lever," and the right operating lever 26R operated in the front-rear direction may be referred to as the "boom operating lever."

The left travel lever 26DL is used to operate the left crawler 1CL. It may be configured to be linked to the left travel pedal. When the left travel lever 26DL is operated in the forward/backward direction, it uses the hydraulic oil discharged by the pilot pump 15 to introduce a control pressure corresponding to the lever operation amount into the pilot port of the control valve 171. The right travel lever 26DR is used to operate the right crawler 1CR. It may be configured to be linked to the right travel pedal. When the right travel lever 26DR is operated in the forward/backward direction, it uses the hydraulic oil discharged by the pilot pump 15 to introduce a control pressure corresponding to the lever operation amount into the pilot port of the control valve 172.

The operation sensor 29 is configured to detect the operation of the operation device 26 by the operator. In this embodiment, the operation sensor 29 detects the operation direction and operation amount of the operation device 26 corresponding to each actuator, and outputs the detected value to the controller 30.

The operation sensor 29 includes operation sensors 29LA, 29LB, 29RA, 29RB, 29DL, and 29DR. The operation sensor 29LA detects the content of the operation of the left operating lever 26L in the forward/rearward direction by the operator, and outputs the detected value to the controller 30. The content of the operation includes, for example, the lever operation direction, the lever operation amount (lever operation angle), etc.

Similarly, the operation sensor 29LB detects the operation of the left operating lever 26L in the left-right direction by the operator, and outputs the detected value to the controller 30. The operation sensor 29RA detects the operation of the right operating lever 26R in the forward-backward direction by the operator, and outputs the detected value to the controller 30. The operation sensor 29RB detects the operation of the right operating lever 26R in the left-right direction by the operator, and outputs the detected value to the controller 30. The operation sensor 29DL detects the operation of the left travel lever 26DL in the forward-backward direction by the operator, and outputs the detected value to the controller 30. The operation sensor 29DR detects the operation of the right travel lever 26DR in the forward-backward direction by the operator, and outputs the detected value to the controller 30.

The controller 30 receives the output of the operation sensor 29, and outputs a control command to the regulator 13 as necessary, changing the discharge volume of the main pump 14. The controller 30 also receives the output of the control pressure sensor 19 provided upstream of the orifice 18, and outputs a control command to the regulator 13 as necessary, changing the discharge volume of the main pump 14. The orifice 18 includes a left orifice 18L and a right orifice 18R, and the control pressure sensor 19 includes negative control pressure sensors 19L and 19R.

[Configuration details for excavator machine control function]
Next, the configuration regarding the machine control function of the shovel 100 will be described in detail with reference to FIG.

Figure 4 shows a portion of the hydraulic system. Specifically, Figure 4(A) shows the hydraulic system portion related to the operation of the arm cylinder 8, and Figure 4(B) shows the hydraulic system portion related to the operation of the boom cylinder 7. Figure 4(C) shows the hydraulic system portion related to the operation of the bucket cylinder 9, and Figure 4(D) shows the hydraulic system portion related to the operation of the swing hydraulic motor 2A.

As shown in FIG. 4, the hydraulic system includes a proportional valve 31. The proportional valve 31 includes proportional valves 31AL to 31DL and 31AR to 31DR.

The proportional valve 31 functions as a control valve for machine control. The proportional valve 31 is disposed in a pipe connecting the pilot pump 15 and the pilot port of the corresponding control valve in the control valve 17, and is configured to be able to change the flow area of the pipe. In this embodiment, the proportional valve 31 operates in response to a control command output by the controller 30. Therefore, the controller 30 can supply the hydraulic oil discharged by the pilot pump 15 to the pilot port of the corresponding control valve in the control valve 17 via the proportional valve 31, regardless of the operation of the operating device 26 by the operator. Then, the controller 30 can apply the pilot pressure generated by the proportional valve 31 to the pilot port of the corresponding control valve.

With this configuration, the controller 30 can operate the hydraulic actuator corresponding to a specific operating device 26 even when no operation is being performed on that specific operating device 26. Furthermore, the controller 30 can forcibly stop the operation of the hydraulic actuator corresponding to that specific operating device 26 even when an operation is being performed on that specific operating device 26.

For example, as shown in FIG. 4(A), the left operating lever 26L is used to operate the arm 5. Specifically, the left operating lever 26L uses hydraulic oil discharged by the pilot pump 15 to apply pilot pressure corresponding to the operation in the forward and backward directions to the pilot port of the control valve 176. More specifically, when the left operating lever 26L is operated in the arm closing direction (rearward), it applies pilot pressure corresponding to the operation amount to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R. Also, when the left operating lever 26L is operated in the arm opening direction (forward), it applies pilot pressure corresponding to the operation amount to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R.

The operation device 26 is provided with a switch SW. In this embodiment, the switch SW includes a switch SW1 and a switch SW2. The switch SW1 is a push button switch provided at the tip of the left operation lever 26L. The operator can operate the left operation lever 26L while pressing the switch SW1. The switch SW1 may be provided on the right operation lever 26R or at another position in the cabin 10. The switch SW2 is a push button switch provided at the tip of the left travel lever 26DL. The operator can operate the left travel lever 26DL while pressing the switch SW2. The switch SW2 may be provided on the right travel lever 26DR or at another position in the cabin 10.

The operation sensor 29LA detects the forward/rearward operation of the left operating lever 26L by the operator and outputs the detected value to the controller 30.

The proportional valve 31AL operates in response to a control command (current command) output by the controller 30. The proportional valve 31AL adjusts the pilot pressure by hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the proportional valve 31AL. The proportional valve 31AR operates in response to a control command (current command) output by the controller 30. The proportional valve 31AR adjusts the pilot pressure by hydraulic oil introduced from the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the proportional valve 31AR. The proportional valve 31AL can adjust the pilot pressure so that the control valve 176L and the control valve 176R can be stopped at any valve position. Similarly, the proportional valve 31AR can adjust the pilot pressure so that the control valve 176L and the control valve 176R can be stopped at any valve position.

With this configuration, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the proportional valve 31AL in response to the arm closing operation by the operator. Furthermore, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the proportional valve 31AL, regardless of the arm closing operation by the operator. In other words, the controller 30 can close the arm 5 in response to the arm closing operation by the operator or regardless of the arm closing operation by the operator.

In addition, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the proportional valve 31AR in response to the arm opening operation by the operator. In addition, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the proportional valve 31AR, regardless of the arm opening operation by the operator. In other words, the controller 30 can open the arm 5 in response to the arm opening operation by the operator or regardless of the arm opening operation by the operator.

In addition, with this configuration, even if the operator is performing an arm closing operation, the controller 30 can, if necessary, reduce the pilot pressure acting on the pilot ports on the closing side of the control valve 176 (the left pilot port of the control valve 176L and the right pilot port of the control valve 176R) to forcibly stop the closing operation of the arm 5. The same applies to the case where the opening operation of the arm 5 is forcibly stopped when the operator is performing an arm opening operation.

Even if the operator is performing an arm closing operation, the controller 30 may, if necessary, control the proportional valve 31AR to increase the pilot pressure acting on the opening pilot port of the control valve 176 (the right pilot port of the control valve 176L and the left pilot port of the control valve 176R) opposite the closing pilot port of the control valve 176, and forcibly return the control valve 176 to the neutral position, thereby forcibly stopping the closing operation of the arm 5. The same applies to the case where the opening operation of the arm 5 is forcibly stopped when the operator is performing an arm opening operation.

Although the explanation with reference to the following Figures 4(B) to 4(D) is omitted, the same applies to the case where the operation of the boom 4 is forcibly stopped when the operator is performing a boom-raising or boom-lowering operation, the case where the operation of the bucket 6 is forcibly stopped when the operator is performing a bucket-closing or bucket-opening operation, and the case where the rotation operation of the upper rotating body 3 is forcibly stopped when the operator is performing a rotation operation.

The same applies when the traveling operation of the lower traveling body 1 is forcibly stopped while the operator is operating the vehicle.

As shown in FIG. 4(B), the right operating lever 26R is used to operate the boom 4. Specifically, the right operating lever 26R uses hydraulic oil discharged by the pilot pump 15 to apply pilot pressure corresponding to operation in the forward and backward directions to the pilot port of the control valve 175. More specifically, when the right operating lever 26R is operated in the boom-up direction (rearward), it applies pilot pressure corresponding to the operation amount to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R. When the right operating lever 26R is operated in the boom-down direction (forward), it applies pilot pressure corresponding to the operation amount to the right pilot port of the control valve 175R.

The operation sensor 29RA detects the forward/rearward operation of the right operating lever 26R by the operator and outputs the detected value to the controller 30.

The proportional valve 31BL operates in response to a control command (current command) output by the controller 30. The proportional valve 31BL adjusts the pilot pressure by hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R via the proportional valve 31BL. The proportional valve 31BR operates in response to a control command (current command) output by the controller 30. The proportional valve 31BR adjusts the pilot pressure by hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 175R via the proportional valve 31BR. The proportional valve 31BL can adjust the pilot pressure so that the control valves 175L and 175R can be stopped at any valve position. The proportional valve 31BR can adjust the pilot pressure so that the control valve 175R can be stopped at any valve position.

With this configuration, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R via the proportional valve 31BL in response to the boom-raising operation by the operator. The controller 30 can also supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R via the proportional valve 31BL, regardless of the boom-raising operation by the operator. In other words, the controller 30 can raise the boom 4 in response to the boom-raising operation by the operator or regardless of the boom-raising operation by the operator.

In addition, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 175R via the proportional valve 31BR in response to the boom lowering operation by the operator. In addition, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 175R via the proportional valve 31BR, regardless of the boom lowering operation by the operator. In other words, the controller 30 can lower the boom 4 in response to the boom lowering operation by the operator or regardless of the boom lowering operation by the operator.

As shown in FIG. 4(C), the right operating lever 26R is also used to operate the bucket 6. Specifically, the right operating lever 26R uses hydraulic oil discharged by the pilot pump 15 to apply pilot pressure corresponding to operation in the left and right directions to the pilot port of the control valve 174. More specifically, when the right operating lever 26R is operated in the bucket closing direction (left direction), it applies pilot pressure corresponding to the amount of operation to the left pilot port of the control valve 174. Also, when the right operating lever 26R is operated in the bucket opening direction (right direction), it applies pilot pressure corresponding to the amount of operation to the right pilot port of the control valve 174.

The operation sensor 29RB detects the left/right operation of the right operating lever 26R by the operator and outputs the detected value to the controller 30.

The proportional valve 31CL operates in response to a control command (current command) output by the controller 30. It adjusts the pilot pressure by the hydraulic oil introduced from the pilot pump 15 to the left pilot port of the control valve 174 via the proportional valve 31CL. The proportional valve 31CR operates in response to a control command (current command) output by the controller 30. It adjusts the pilot pressure by the hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 174 via the proportional valve 31CR. The proportional valve 31CL can adjust the pilot pressure so that the control valve 174 can be stopped at any valve position. Similarly, the proportional valve 31CR can adjust the pilot pressure so that the control valve 174 can be stopped at any valve position.

With this configuration, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 174 via the proportional valve 31CL in response to the bucket closing operation by the operator. The controller 30 can also supply hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 174 via the proportional valve 31CL, regardless of the bucket closing operation by the operator. In other words, the controller 30 can close the bucket 6 in response to the bucket closing operation by the operator or regardless of the bucket closing operation by the operator.

In addition, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 174 via the proportional valve 31CR in response to the bucket opening operation by the operator. In addition, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 174 via the proportional valve 31CR, regardless of the bucket opening operation by the operator. In other words, the controller 30 can open the bucket 6 in response to the bucket opening operation by the operator or regardless of the bucket opening operation by the operator.

As shown in FIG. 4(D), the left operating lever 26L is also used to operate the turning mechanism 2. Specifically, the left operating lever 26L uses hydraulic oil discharged by the pilot pump 15 to apply pilot pressure corresponding to the operation in the left and right directions to the pilot port of the control valve 173. More specifically, when the left operating lever 26L is operated in the left turning direction (left direction), it applies pilot pressure corresponding to the operation amount to the left pilot port of the control valve 173. Also, when the left operating lever 26L is operated in the right turning direction (right direction), it applies pilot pressure corresponding to the operation amount to the right pilot port of the control valve 173.

The operation sensor 29LB detects the left/right operation of the left operating lever 26L by the operator and outputs the detected value to the controller 30.

The proportional valve 31DL operates in response to a control command (current command) output by the controller 30. It adjusts the pilot pressure by the hydraulic oil introduced from the pilot pump 15 to the left pilot port of the control valve 173 via the proportional valve 31DL. The proportional valve 31DR operates in response to a control command (current command) output by the controller 30. It adjusts the pilot pressure by the hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 173 via the proportional valve 31DR. The proportional valve 31DL can adjust the pilot pressure so that the control valve 173 can be stopped at any valve position. Similarly, the proportional valve 31DR can adjust the pilot pressure so that the control valve 173 can be stopped at any valve position.

With this configuration, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 173 via the proportional valve 31DL in response to a left rotation operation by the operator. The controller 30 can also supply hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 173 via the proportional valve 31DL, regardless of a left rotation operation by the operator. In other words, the controller 30 can rotate the rotation mechanism 2 to the left in response to a left rotation operation by the operator or regardless of a left rotation operation by the operator.

In addition, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 173 via the proportional valve 31DR in response to a right turning operation by the operator. In addition, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 173 via the proportional valve 31DR, regardless of a right turning operation by the operator. In other words, the controller 30 can rotate the turning mechanism 2 to the right in response to a right turning operation by the operator or regardless of a right turning operation by the operator.

The left travel lever 26DL is used to operate the left crawler 1CL. Specifically, the left travel lever 26DL uses hydraulic oil discharged by the pilot pump 15 to apply pilot pressure to the pilot port of the control valve 171 according to the forward/rearward operation. The operation sensor 29DL electrically detects the forward/rearward operation of the left travel lever 26DL by the operator and outputs a current command indicating the detected value to the controller 30. This causes the controller 30 to operate according to the current command.

The controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 171 via a proportional valve (not shown) in the same manner as in the configuration described above. In other words, the left crawler 1CL can be moved forward. The controller 30 can also supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 171 via a proportional valve (not shown). In other words, the left crawler 1CL can be moved backward.

The right travel lever 26DR is used to operate the right crawler 1CR. Specifically, the right travel lever 26DR uses hydraulic oil discharged by the pilot pump 15 to apply pilot pressure to the pilot port of the control valve 172 according to the operation in the forward or backward direction. The operation sensor 29DR electrically detects the operation of the right travel lever 26DR in the forward or backward direction by the operator, and outputs a current command indicating the detected value to the controller 30. This causes the controller 30 to operate according to the current command.

The controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 172 via the proportional valve 31, in the same manner as in the configuration described above. In other words, the right crawler 1CR can be moved forward. The controller 30 can also supply hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 172 via the proportional valve 31. In other words, the right crawler 1CR can be moved backward.

The excavator 100 may also be configured to automatically operate the bucket tilt mechanism. In this case, the hydraulic system portion related to the bucket tilt cylinder that constitutes the bucket tilt mechanism may be configured in the same manner as the hydraulic system portion related to the operation of the boom cylinder 7, etc.

Although the description has been given of an electric control lever as the form of the operating device 26, a hydraulic operating lever may be used instead of an electric operating lever. In this case, the lever operation amount of the hydraulic operating lever may be detected in the form of pressure by a pressure sensor and input to the controller 30. In addition, a solenoid valve may be disposed between the operating device 26 as a hydraulic operating lever and the pilot port of each control valve. The solenoid valve is configured to operate in response to an electric signal from the controller 30. With this configuration, when manual operation is performed using the operating device 26 as a hydraulic operating lever, the operating device 26 can move each control valve by increasing or decreasing the pilot pressure in response to the lever operation amount. In addition, each control valve may be configured as an electromagnetic spool valve. In this case, the electromagnetic spool valve operates in response to an electric signal from the controller 30 corresponding to the lever operation amount of the electric operating lever.

[Configuration details for excavator load weight detection function]
Next, a configuration related to a function for detecting the weight of a load (e.g., earth and sand) of the shovel 100 according to this embodiment will be described with reference to Fig. 5. Fig. 5 is a diagram illustrating an example of a configuration part related to the weight detection function of the shovel 100 according to this embodiment.

As described above in FIG. 3, the controller 30 includes a weight processing unit 60 as a functional unit related to the function of detecting the weight of the load, such as soil and sand, excavated by the bucket 6.

The weight processing unit 60 has a load weight calculation unit 61, a weight determination unit 62, a maximum load detection unit 63, an added load calculation unit 64, a remaining load calculation unit 65, and a load center of gravity calculation unit 66.

Here, we will explain an example of the operation of loading soil (cargo) onto a dump truck using the excavator 100 according to this embodiment.

First, the shovel 100 controls the attachment at the excavation position to excavate soil and sand with the bucket 6 (excavation operation). Next, the shovel 100 performs an operation to raise the boom 4. In addition to the operation to raise the boom 4, the shovel 100 calculates the weight of the soil and sand (load) in the bucket 6 using the load weight calculation unit 61.

Next, the shovel 100 rotates the upper rotating body 3 to move the bucket 6 from the excavation position to the discharge position (swing operation). Below the discharge position, the bed of the dump truck is located. Next, at the discharge position, the shovel 100 controls the attachment to discharge the load (soil and sand) in the bucket 6, thereby loading the load in the bucket 6 onto the bed of the dump truck (discharge operation).

In the excavator 100 according to this embodiment, it is determined whether the soil in the bucket 6 has spilled out based on the weight of the soil (an example of a load) in the bucket 6 calculated by the load weight calculation unit 61 before the soil in the bucket 6 (an example of a load) is released. If it is determined that the soil has spilled out, a process such as a notification to the operator is performed.

Next, the excavator 100 rotates the upper rotating body 3 and moves the bucket 6 from the discharge position to the excavation position (rotation operation). By repeating these operations, the excavator 100 loads the excavated soil (an example of a load) onto the bed of the dump truck.

The load weight calculation unit 61 calculates the weight of the load (e.g., soil) in the bucket 6. The load weight calculation unit 61 in this embodiment calculates the weight of the load (e.g., soil) based on the thrust of the boom cylinder 7.

The load weight calculation unit 61 according to this embodiment constantly calculates the weight of the load (e.g., soil and sand) after the load is loaded onto the bucket 6. For this reason, it is necessary to set conditions for adopting the calculated load weight as the actual load weight. Therefore, in this embodiment, one of the load weights measured twice at different positions by the load weight calculation unit 61 is adopted.

Specifically, while the load is being transported by the bucket 6 (an example of a work tool), the weight determination unit 62 determines whether the difference in the weight of the load measured twice at different positions by the load weight calculation unit 61 is equal to or greater than a determination threshold (an example of a predetermined value). The determination threshold is a value determined as a standard for determining whether part of the load has fallen off, and is a value determined according to the embodiment, such as the weight of the load.

In other words, in this embodiment, the weight determination unit 62 determines whether the difference between the weights of the load measured twice is equal to or greater than the determination threshold, thereby determining whether part of the load has fallen off during transport by the bucket 6.

If the weight determination unit 62 determines that the difference between the two weight measurements is equal to or greater than the judgment threshold, it uses the later of the two weight measurements as the measured value. If the weight determination unit 62 determines that the difference between the weights is smaller than the judgment threshold, it uses the earlier of the two weight measurements as the measured value.

In other words, the earlier of the two measured weights of the load is the weight of the load calculated by the load weight calculation unit 61 based on the thrust of the boom cylinder 7 acquired at a predetermined first position when the bucket 6 reaches the first position. The first position is a position where the thrust of the boom cylinder 7 is estimated to contain less noise, for example, a position where the bucket 6 reaches a preset height during the raising operation of the boom 4.

The latter of the two measured weights of the load is the weight of the load calculated by the load weight calculation unit 61 based on the thrust of the boom cylinder 7 obtained at the second position when the bucket 6 reaches the predetermined second position. The second position is a position for determining whether or not part of the load has spilled out of the bucket 6 while the bucket 6 is moving, and is, for example, a position where the bottom of the bucket 6 is inside the bed of the dump truck after the swing operation is completed.

The specific determination made by the weight determination unit 62 will be described later.

The maximum load detection unit 63 detects the maximum load of the dump truck to be loaded with soil and sand. For example, the maximum load detection unit 63 identifies the dump truck to be loaded with soil and sand based on the image captured by the imaging device S6. Next, the maximum load detection unit 63 detects the maximum load of the dump truck based on the image of the identified dump truck. For example, the maximum load detection unit 63 determines the vehicle type (size, etc.) of the dump truck based on the image of the identified dump truck. The maximum load detection unit 63 has a table that associates vehicle types with maximum loads, and determines the maximum load of the dump truck based on the vehicle type and table determined from the image. Note that the maximum load, vehicle type, etc. of the dump truck may be input by the input device 42, and the maximum load detection unit 63 may determine the maximum load of the dump truck based on the input information of the input device 42.

The additional load calculation unit 64 calculates the weight of the load loaded on the dump truck. That is, each time the soil in the bucket 6 is discharged onto the bed of the dump truck, the additional load calculation unit 64 adds the weight of the load in the bucket 6 calculated by the load weight calculation unit 61 to calculate the additional load (total weight), which is the sum of the weights of the loads loaded onto the bed of the dump truck. Note that if the dump truck to which the soil is to be loaded becomes a new dump truck, the additional load is reset.

The remaining load calculation unit 65 calculates the remaining load as the difference between the maximum load of the dump truck detected by the maximum load detection unit 63 and the current added load calculated by the added load calculation unit 64. The remaining load is the remaining weight of soil that can be loaded onto the dump truck.

The load center of gravity calculation unit 66 calculates the center of gravity of the load (e.g., soil and sand) in the bucket 6. For example, the load center of gravity calculation unit 66 may calculate the center of gravity of the load based on the values of the boom angle sensor S1, the arm angle sensor S2, the bucket angle sensor S3, etc., assuming that the positional relationship between the tip of the bucket 6 and the center of gravity of the load is known. Note that the calculation method is not limited to this, and various methods can be used.

The information transmission unit 53 in this embodiment may display on the display device 40 one or more of the weight of the load in the bucket 6 calculated by the load weight calculation unit 61, the maximum load of the dump truck detected by the maximum load detection unit 63, the added load of the dump truck (the total weight of the load loaded on the bed) calculated by the added load calculation unit 64, and the remaining load of the dump truck (the remaining weight of the soil that can be loaded) calculated by the remaining load calculation unit 65.

If the added load capacity exceeds the maximum load capacity, the information transmission unit 53 may display a warning on the display device 40. If the calculated weight of the load in the bucket 6 exceeds the remaining load capacity, the information transmission unit 53 may display a warning on the display device 40.

[Load Weight Calculation Method in Load Weight Calculation Unit 61]
Next, a method for calculating the weight of soil and sand (load) in the bucket 6 in the load weight calculation unit 61 of the shovel 100 according to this embodiment will be described with reference to FIG. 5 and FIG. 6 .

Figure 6 is a schematic diagram explaining parameters related to calculation of the weight of a load on an attachment of a shovel 100. Figure 6(a) shows the shovel 100, and Figure 6(b) shows the vicinity of the bucket 6. In the following explanation, it is assumed that a pin P1, the bucket center of gravity G3, and the center of gravity Gs of the load, which will be described later, are located on a horizontal line L1.

In the configuration of the excavator 100 according to this embodiment, a pin P1 connects the upper rotating body 3 and the boom 4. A pin P2 connects the upper rotating body 3 and the boom cylinder 7. A pin P3 connects the boom 4 and the boom cylinder 7. A pin P4 connects the boom 4 and the arm cylinder 8. A pin P5 connects the arm 5 and the arm cylinder 8. A pin P6 connects the boom 4 and the arm 5. A pin P7 connects the arm 5 and the bucket 6.

Pin P7 functions as a rotation mechanism that rotates bucket 6.

Figure 6(a) shows the center of gravity G1 of the boom 4, the center of gravity G2 of the arm 5, the center of gravity G3 of the bucket 6, and the center of gravity GS of the object loaded into the bucket 6. The reference line L2 shown in Figure 6(b) is a line that passes through the pin P7 and is parallel to the opening surface of the bucket 6.

The distance between pin P1 and the center of gravity G1 of the boom 4 is D1. The distance between pin P1 and the center of gravity G2 of the arm 5 is D2. The distance between pin P1 and the center of gravity G3 of the bucket 6 is D3. The distance between pin P1 and the center of gravity GS of the transported object is Ds. The distance between pin P1 and the line connecting pins P2 and P3 and pin P1 is Dc. The detected cylinder pressure value of the boom cylinder 7 is Fb. The vertical component of the boom weight perpendicular to the line connecting pin P1 and the boom center of gravity G1 is W1a. The vertical component of the arm weight perpendicular to the line connecting pin P1 and the arm center of gravity G2 is W2a. The weight of the bucket 6 is W3, and the weight of the load (e.g., soil and sand) loaded on the bucket 6 is Ws.

As shown in FIG. 6(a), the position of pin P7 is calculated from the boom angle and the arm angle. That is, the position of pin P7 can be calculated based on the detection values of the boom angle sensor S1 and the arm angle sensor S2.

As shown in FIG. 6B, the positional relationship between the pin P7 and the bucket center of gravity G3 (the angle between the reference line L2 of the bucket 6 and the line connecting the pin P7 and the bucket center of gravity G3 is indicated as θ4, and the distance between the pin P7 and the bucket center of gravity G3 is indicated as D4) is a specified value. The positional relationship between the pin P7 and the center of gravity Gs of the load (the angle between the reference line L2 of the bucket 6 and the line connecting the pin P7 and the center of gravity Gs of the load is indicated as θ5, and the distance between the pin P7 and the center of gravity Gs of the load is indicated as D5) is determined in advance, for example, experimentally and stored in the controller 30. That is, the center of gravity Gs of the load and the bucket center of gravity G3 can be estimated based on the bucket angle sensor S3.

That is, the load center of gravity calculation unit 66 can estimate the center of gravity Gs of the load based on the detection values of the boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3.

Next, the equation for the balance between each moment around pin P1 and boom cylinder 7 can be expressed by the following equation (1).

WsDs+W1aD1+W2aD2+W3D3=FbDc...(1)

When equation (1) is expanded for the weight Ws of the load, it can be expressed as the following equation (2).

Ws=(FbDc-(W1aD1+W2aD2+W3D3))/Ds...(2)

Here, the detected cylinder pressure value Fb of the boom cylinder 7 is calculated by the boom rod pressure sensor S7R and the boom bottom pressure sensor S7B. The distance Dc and the weight of the vertical component W1a are calculated by the boom angle sensor S1. The weight of the vertical component W2a and the distance D2 are calculated by the boom angle sensor S1 and the arm angle sensor S2. The distance D1 and the weight W3 are known values. In addition, the distance Ds and the distance D3 are also estimated by estimating the center of gravity Gs of the load and the center of gravity G3 of the bucket.

The weight Ws of the load can therefore be calculated based on the detected cylinder pressure of the boom cylinder 7 (detected values of the boom rod pressure sensor S7R and the boom bottom pressure sensor S7B), the boom angle (detected value of the boom angle sensor S1), and the arm angle (detected value of the arm angle sensor S2). As a result, the load weight calculation unit 61 calculates the weight Ws of the load based on the center of gravity Gs of the load estimated by the load center of gravity calculation unit 66.

Whether the excavator 100 is in normal operation can be determined by estimating the attachment posture based on the detection value of the pilot of the bucket cylinder 9.

In the above description, the attitude of the bucket 6 during the specified operation is assumed to be horizontal, the center of gravity of the load is estimated, and the weight of the load is calculated, but this is not limited to the above. For example, the bucket 6 may be imaged by a camera S6F that images the front, and the attitude of the bucket 6 may be estimated based on the image. Also, the bucket 6 may be imaged by a camera S6F, and if it is determined that the attitude of the bucket 6 is horizontal based on the image, the center of gravity of the load may be estimated and the weight of the load may be calculated.

Next, the timing of calculation of the weight of the load performed during loading operation with the bucket 6 will be described. FIG. 7 is a diagram showing the movement trajectory of the bucket 6 until the load is loaded onto the dump truck DT. For ease of explanation, the excavator 100, excluding the bucket 6, is omitted from FIG. 7. The dotted line shown in FIG. 7 indicates the trajectory of the movement of the bucket 6.

The maximum load capacity of the dump truck DT shown in FIG. 7 has already been detected by the maximum load capacity detection unit 63.

In the example shown in FIG. 7, position PT1 is the position where the excavation operation of the shovel 100 is completed and a load is loaded into the bucket 6. After the excavation operation by the shovel 100 is completed, the load weight calculation unit 61 starts calculating the weight of the load (e.g., soil) in the bucket 6. The load weight calculation unit 61 calculates the weight of the load based on the detection value of the cylinder pressure of the boom cylinder 7.

Position PT2 is a position of the excavator 100 that is a candidate for the weight of the actual load. Position PT2 is at a height Ha from position PT1. As shown in FIG. 7, the weight of the load measured when the height (length in the Z-axis direction) of the bucket 6 becomes equal to or greater than a predetermined height value Ha from position PT1 is used as a candidate for the weight of the actual load (hereinafter also referred to as the first detection value).

In other words, the load weight calculation unit 61 according to this embodiment always calculates the weight of the load (e.g., soil) based on the thrust of the boom cylinder 7. However, when the upper rotating body 3 rotates, a rotation centrifugal force and an inertial force are applied, which can easily cause an error in the calculated weight of the load (e.g., soil).

The load weight calculation unit 61 in this embodiment therefore sets a height of the bucket 6 (e.g., a predetermined height Ha) for calculating a weight that is less likely to produce errors (less likely to include noise) in advance, and uses the weight of the load (e.g., soil) calculated when the bucket 6 reaches the position of the predetermined height Ha (e.g., position PT2) as a candidate for the actual weight of the load (first detection value).

In this embodiment, the operator of the shovel 100 performs a combined operation using the operating device 26. In the example shown in FIG. 7, the operator performs a combined operation including a boom 4 raising operation and a right turning operation. The bucket 6 moves in the +Z direction and the −X direction in response to a control signal from the controller 30 corresponding to the operation.

The boom 4 is raised until it reaches a height Hd or higher, which is the height required to load the cargo onto the bed of the dump truck DT. The operator basically performs this combined operation so that soil and sand do not spill out of the bucket 6.

In the example shown in FIG. 7, two measurements are taken: a first measurement of the weight of the load is taken while the boom 4 is being raised, and a second measurement of the weight of the load is taken after the boom 4 is raised and the upper rotating body 3 has started to rotate.

In other words, after the load weight calculation unit 61 calculates the weight of the load at position PT2 as the first measurement, there is a possibility that part of the load will fall out of the bucket 6 while the bucket 6 is moving and before it is loaded onto the dump truck DT.

In the example shown in FIG. 7, position PT3 indicates the position where part of the load SF1 has spilled out of the bucket 6. If part of the load SF1 has spilled out, a discrepancy occurs between the weight of the load measured at position PT2 and the weight of the load that is actually loaded onto the dump truck DT. Therefore, in this embodiment, the weight determination unit 62 determines whether the load has spilled out.

Therefore, the load weight calculation unit 61 calculates the weight of the load at position PT4 as the second measurement.

Position PT4 is the position of the bucket 6 where the weight of the load is calculated to determine whether the load has spilled. Position PT4 is at a sufficient height to load the dump truck DT, and is at least a height Hd (height of the dump truck DT) from position PT1. Position PT4 is the position after the upper rotating body 3 of the excavator 100 has been rotating for a specified time or more, and for example, the bucket 6 is inside the bed of the dump truck DT. The specified time is set in advance based on the time required for the bucket 6 to come inside the bed of the dump truck DT, etc.

The weight determination unit 62 determines whether the difference between the weight of the load calculated at position PT2 and the weight of the load calculated at position PT4 is equal to or greater than a determination threshold (an example of a predetermined value).

If the weight determination unit 62 determines that the weight difference is equal to or greater than the judgment threshold, it uses the second detection value calculated at position PT4 (the later of the two weight measurements) as the measurement of the actual weight of the load. On the other hand, if the weight determination unit 62 determines that the weight difference is smaller than the judgment threshold, it uses the first detection value calculated at position PT2 (the earlier of the two weight measurements) as the measurement of the actual weight of the load.

In other words, if the weight determination unit 62 determines that the weight difference is less than the judgment threshold, it assumes that the load did not fall off and adopts the weight calculated at position PT2, which is less likely to contain noise (the earlier of the two weight measurements), as the measured weight of the load. In addition, if the weight determination unit 62 determines that the weight difference is greater than or equal to the judgment threshold, it adopts the weight calculated after the load fell off (the earlier of the two weight measurements), which may contain noise, as the measured weight of the load.

When the weight determination unit 62 determines that the difference between the weights measured twice by the weight determination unit 62 is equal to or greater than the determination threshold, the information transmission unit 53 may display a warning on the display device 40. Note that the output of the warning by the information transmission unit 53 is not limited to the display device 40, and may be an audio output by the audio output device 43. Based on the warning, the operator may stop the operation of discharging the load onto the dump truck DT and start again from loading the load, or may continue the operation of discharging the load onto the dump truck DT.

When the operator performs the discharge operation, the load in the bucket 6 is dropped from inside the bucket 6 onto the bed of the dump truck DT outside the bucket 6.

Then, the additional load calculation unit 64 calculates the weight of the load loaded on the dump truck. Specifically, the additional load calculation unit 64 adds the weight of the load in the bucket 6 adopted by the weight determination unit 62 to calculate the additional load (total weight), which is the sum of the weights of the loads loaded on the bed of the dump truck.

The remaining load calculation unit 65 calculates the remaining load as the difference between the maximum load of the dump truck detected by the maximum load detection unit 63 and the current added load calculated by the added load calculation unit 64.

In this way, provided that the bucket 6 is directly above the bed of the dump truck DT, the load amount (total weight), which is the sum of the weights of the loads loaded on the bed of the dump truck DT, is updated each time the load is discharged from the bucket 6.

Figure 8 is a flowchart showing the processing procedure up to loading a load by the shovel 100 into the dump truck DT according to this embodiment. The example shown in Figure 8 shows the processing after the excavation operation by the shovel 100 is completed and the load of the load into the bucket 6 is completed.

First, after the excavation operation is completed, the load weight calculation unit 61 starts calculating (measuring) the weight of the load loaded on the bucket 6 (S801). As described above, the load weight is calculated based on the detection value of the cylinder pressure of the boom cylinder 7 (detection value of the boom rod pressure sensor S7R and the boom bottom pressure sensor S7B), the boom angle (detection value of the boom angle sensor S1), and the arm angle (detection value of the arm angle sensor S2).

Then, the controller 30 starts control of raising the boom 4 in accordance with the operation from the operator (S802). The controller 30 then determines whether the height of the bucket 6 is equal to or greater than a predetermined height Ha (S803). If it is less than the predetermined height Ha (S803: No), the controller 30 repeats the determination until the height of the bucket 6 reaches the predetermined height Ha.

On the other hand, if the controller 30 determines that the height of the bucket 6 is equal to or greater than the predetermined height Ha (S803: Yes), the load weight calculation unit 61 acquires the currently calculated weight of the load as a first detection value (an example of a measured value) that is a candidate for use as the actual weight (S804).

The controller 30 then starts controlling the rotation operation of the upper rotating body 3 (S805). The rotation control may be combined with the raising control of the boom 4, or each may be controlled separately. The raising control of the boom 4 is performed until the height of the bucket 6 reaches or exceeds the height Hd required to load the load onto the bed of the dump truck DT.

The controller 30 determines whether the time during which the upper rotating body 3 is rotating is equal to or longer than a specified time (S806). The specified time is determined based on the time required for the bucket 6 to reach the bed of the dump truck DT, etc. If the time during which the upper rotating body 3 is rotating is not equal to or longer than the specified time (S806: No), the controller 30 repeats this determination.

On the other hand, if the controller 30 determines that the time during which the upper rotating body 3 has been rotating is equal to or longer than the specified time (S806: Yes), the load weight calculation unit 61 acquires the currently measured weight of the load as a second detection value (an example of a measured value) that is a candidate for use as the actual weight (S807).

The weight determination unit 62 determines whether or not |First detection value - Second detection value| < the determination threshold is satisfied (S808). If the weight determination unit 62 determines that this condition is satisfied (the load has not fallen off) (S808: Yes), the weight determination unit 62 provisionally determines the first detection value as the actual weight of the load (S809).

If the weight determination unit 62 determines that the condition is not met (part of the load has fallen) (S808: No), the information transmission unit 53 displays a warning on the display device 40 so that the operator can recognize that the load has fallen (S810). Then, the weight determination unit 62 provisionally determines the second detection value as the actual weight of the load (S811). Furthermore, the controller 30 writes information for understanding that part of the load has fallen during this loading into the history information regarding the loading of the load. The history information is information that has been saved as a history of the operations performed by the excavator 100, and is stored, for example, in the storage device 47.

After that, when the controller 30 determines that the load in the bucket 6 has been discharged onto the bed of the dump truck DT by the operator's operation, the weight determination unit 62 confirms the provisionally confirmed weight of the load (S812).

After the first or second detection value (an example of a measured value) is adopted, the weight determination unit 62 according to this embodiment confirms the adopted first or second detection value (an example of a measured value) by the operation of the bucket 6 to discharge the load onto the bed of the dump truck DT. In other words, the first or second detection value (an example of a measured value) is not confirmed unless the operation of the bucket 6 to discharge the load onto the bed of the dump truck DT is performed. In other words, if the load is not discharged onto the bed after the weight is provisionally confirmed in S809 or S811 before the weight is confirmed in S812, the provisional confirmation of the weight of the load can be canceled.

Then, the added load calculation unit 64 accumulates the weight of the load loaded on the dump truck DT (S813). Furthermore, the remaining load calculation unit 65 calculates the difference between the maximum load of the dump truck DT and the current added load calculated by the added load calculation unit 64 as the remaining load.

The above-mentioned processing procedure makes it possible to calculate the weight of the load on the dump truck DT, taking into account the case where part of the load falls out of the bucket 6.

In the processing procedure shown in FIG. 8, an example has been described in which, when it is determined that part of the load has fallen, the information is written into the history information and an alarm (one example of information indicating that part of the load has fallen) is output. However, the processing performed when it is determined that part of the load has fallen is not limited to the control of writing the information into the history information and outputting an alarm.

As a modified example, when the weight determination unit 62 determines that part of the load has fallen, the loading of the load onto the bed of the dump truck DT is stopped, and the excavation operation by the excavator 100 is resumed. To perform this control, the controller 30 may automatically control the bucket 6 to return to the excavated position, or may control the bucket 6 to return to the excavated position according to the operation by the operator.

In this embodiment, the controller 30 has the above-described configuration, and can therefore determine whether soil has spilled from the bucket 6 between the end of the excavation operation and the start of the discharge operation. Furthermore, the controller 30 can more accurately calculate the load, which is the amount of cargo loaded on the dump truck DT.

In this embodiment, an example has been described in which the amount of rotation is determined based on whether the time for the rotation operation of the upper rotating body 3 is equal to or greater than a specified time. However, this embodiment does not limit the determination of the amount of rotation to be based on a specified time, and the amount of rotation may also be determined based on whether the rotation angle of the upper rotating body 3 is equal to or greater than a specified angle.

Second Embodiment
In the first embodiment, an example was described in which, when the weight of the load is detected twice, the second weight of the load is detected after the upper rotating body 3 has rotated. However, the first embodiment does not limit the detection of the second weight of the load to after the rotation. Therefore, in the second embodiment, an example is described in which the second weight of the load is detected at a different timing from that in the first embodiment. Note that the configuration of the excavator 100 is the same as that in the first embodiment, and a description thereof will be omitted.

In the second embodiment, an example is described in which the weight of the load is detected for the second time during the raising operation of the boom 4. In this embodiment, an example is described in which the weight of the load is detected for the second time during the raising operation of the boom 4. For example, when excavating soil, soil that is located at a lower level than the ground where the shovel 100 is located may be loaded into the bucket 6. In such a case, the distance that the bucket 6 moves in the height direction becomes longer, and there is a possibility that part of the load will fall out of the bucket 6 during the raising operation.

Therefore, in this embodiment, the load weight calculation unit 61 performs two measurements: a first measurement of the load weight, then a lifting operation of the boom 4 is performed, and a second measurement of the load weight is performed after the lifting operation.

Figure 9 is a flowchart showing the processing procedure up to loading a load by the shovel 100 into the dump truck DT according to this embodiment. The example shown in Figure 9 shows the processing after the excavation operation by the shovel 100 is completed and the load of the load into the bucket 6 is completed.

First, after the excavation operation is completed, the load weight calculation unit 61 starts calculating (measuring) the weight of the load loaded on the bucket 6 (S901).

Then, the controller 30 starts control of raising the boom 4 in accordance with the operation from the operator (S902). The controller 30 then determines whether the height of the bucket 6 is equal to or greater than the predetermined first height Ha1 (S903). If it is smaller than the predetermined first height Ha1 (S903: No), the process is repeated until the height of the bucket 6 reaches the predetermined first height Ha1. The predetermined first height Ha1 is determined based on a height at which it is assumed that there is less noise contained in the thrust of the boom cylinder 7 when the raising operation of the boom 4 is started from the position where the load is loaded.

On the other hand, if the controller 30 determines that the height of the bucket 6 is equal to or greater than the predetermined first height Ha1 (S903: Yes), the load weight calculation unit 61 acquires the currently calculated weight of the load as the first detection value, which is a candidate for use as the actual weight (S904).

The controller 30 continues to perform the raising operation of the boom 4. Then, the controller 30 determines whether the height of the bucket 6 is equal to or greater than the predetermined second height Ha2 (S905). If it is less than the predetermined second height Ha2 (S905: No), the process is repeated until the height of the bucket 6 reaches the predetermined second height Ha2. The predetermined second height Ha2 is a position higher than the predetermined first height Ha1, and is, for example, a height at which a load can be discharged from the bucket 6 onto the bed of the dump truck DT.

On the other hand, if the controller 30 determines that the height of the bucket 6 is equal to or greater than the predetermined second height Ha2 (S905: Yes), the load weight calculation unit 61 acquires the currently calculated weight of the load as a second detection value, which is a candidate for use as the actual weight (S906).

The weight determination unit 62 determines whether or not |First detection value - Second detection value| < the determination threshold is satisfied (S907). If the weight determination unit 62 determines that this condition is satisfied (the load has not fallen off) (S907: Yes), the weight determination unit 62 provisionally determines the first detection value as the actual weight of the load (S908).

If the weight determination unit 62 determines that the condition is not met (part of the load has fallen off) (S907: No), the information transmission unit 53 displays a warning on the display device 40 so that the operator can recognize that part of the load has fallen off (S909). Then, the weight determination unit 62 provisionally determines the second detection value as the actual weight of the load (S910). Furthermore, the controller 30 writes information for understanding that part of the load has fallen off during this loading into the history information regarding the loading of the load.

After that, when the controller 30 determines that the load in the bucket 6 has been discharged onto the bed of the dump truck DT by the operator's operation, the weight determination unit 62 confirms the provisionally confirmed weight of the load (S911).

Then, the added load calculation unit 64 accumulates the weight of the load loaded on the dump truck DT (S912). Furthermore, the remaining load calculation unit 65 calculates the difference between the maximum load of the dump truck DT and the current added load calculated by the added load calculation unit 64 as the remaining load.

The above-mentioned processing procedure makes it possible to calculate the weight of the load on the dump truck DT, taking into account the case where part of the load falls out of the bucket 6.

In the processing procedure shown in FIG. 9, an example has been described in which, when it is determined that part of the load has fallen, the information is written to the history information and an alarm (one example of information indicating that part of the load has fallen) is output. However, the processing performed when it is determined that part of the load has fallen is not limited to control of writing the information to the history information and outputting an alarm. For example, when it is determined by the weight determination unit 62 that part of the load has fallen, the loading of the load onto the bed of the dump truck DT may be stopped, and the excavation operation by the excavator 100 may be resumed.

According to the excavator 100 (an example of a work machine) of the embodiment described above, the controller 30 calculates the weight of the load twice, and if the difference between the two load weights is less than a judgment threshold (an example of a predetermined value), the earlier of the two load weights is used as the weight of the load, thereby suppressing the effects of noise and improving the weight measurement accuracy. Also, if the difference between the two load weights is equal to or greater than the judgment threshold (an example of a predetermined value), the later of the two load weights is used, which takes into account that part of the load has fallen off, thereby improving the weight measurement accuracy.

According to the excavator 100 (an example of a work machine) of the embodiment described above, the controller 30 calculates the weight of the load twice, and if the difference between the weights of the load in the two loads is smaller than a judgment threshold (an example of a predetermined value), the weight of the load measured earlier of the two loads is used as the weight of the load, thereby suppressing the effects of noise and improving the measurement accuracy of the weight of the load loaded onto the dump truck DT. Also, if the difference between the weights of the load in the two loads is equal to or greater than the judgment threshold (an example of a predetermined value), the weight of the load measured later of the two loads is used, which takes into account that part of the load has fallen off, thereby improving the measurement accuracy of the weight of the load loaded onto the dump truck DT.

Third Embodiment
In the above-described embodiment, a description has been given of control relating to the weight of a load on the bucket 6. However, when controlling the weight of a load, the implement provided at the tip of the attachment of the work machine is not limited to the bucket 6. Therefore, in the third embodiment, a case will be described in which the implement provided at the tip of the attachment of the work machine is a lifting magnet.

Figure 10 is a side view of the work machine 200 according to this embodiment. An upper rotating body 203 is mounted on a lower traveling body 201 of the work machine 200 via a rotating mechanism 202. A boom 204 is attached to the upper rotating body 203. An arm 205 is attached to the tip of the boom 204, and a lifting magnet 206 is attached to the tip of the arm 205 as an end attachment (work tool). The boom 204 and the arm 205 constitute a work attachment, which is an example of an attachment. The boom 204 is driven by a boom cylinder 207 (an example of a hydraulic cylinder), the arm 205 is driven by an arm cylinder 208 (an example of a hydraulic cylinder), and the lifting magnet 206 is driven by a lifting magnet cylinder 209 (an example of a hydraulic cylinder). In this embodiment, the work tool (transport mechanism) that is attached to the tip of the attachment and can be used to transport the transported object is a lifting magnet 206, but depending on the type of work, other work tools such as a grapple, a demolition fork, or a harvester including a chainsaw may be attached.

A boom angle sensor S201 is attached to the boom 204, an arm angle sensor S202 is attached to the arm 205, and a lifting magnet angle sensor S203 is attached to the lifting magnet 206. An operation device 26, a controller 230, a display device 40, a spatial recognition device 280, a machine tilt sensor S204, and a rotation angular velocity sensor S205 are attached to the upper rotating body 203. Note that the operation device 26 and the display device 40 are the same as in the above-mentioned embodiment, so a description thereof will be omitted.

The boom angle sensor S201 is configured to detect the boom angle, which is the rotation angle of the boom 204 relative to the upper rotating body 203. The boom angle sensor S201 may be, for example, a rotation angle sensor that detects the rotation angle of the boom 204 around the boom foot pin, a cylinder stroke sensor that detects the stroke amount (boom stroke amount) of the boom cylinder 207, or an inclination (acceleration) sensor that detects the inclination angle of the boom 204, or may be a combination of an acceleration sensor and a gyro sensor. The same is true for the arm angle sensor S202 that detects the arm angle that is the rotation angle of the arm 205 relative to the boom 204, and the lifting magnet angle sensor S203 that detects the lifting magnet angle that is the rotation angle of the lifting magnet 206 relative to the arm 205.

The machine body inclination sensor S204 is configured to detect the inclination (machine body inclination angle) of the upper rotating body 203 relative to the horizontal plane. In this embodiment, the machine body inclination sensor S204 is an acceleration sensor that detects the inclination angle around the fore-aft axis and the lateral axis of the upper rotating body 203. The fore-aft axis and the lateral axis of the upper rotating body 203 are, for example, perpendicular to each other and pass through the machine center point, which is a point on the rotation axis of the work machine 200.

The rotation angular velocity sensor S205 detects the rotation angular velocity of the upper rotating body 203. In this embodiment, it is a gyro sensor. It may also be a resolver, a rotary encoder, etc.

The spatial recognition device 280 is configured to capture images of the surroundings of the work machine 200. The spatial recognition device 280 is, for example, a monocular camera, a stereo camera, a distance imaging camera, an infrared camera, or a LIDAR. In the example of FIG. 10, the spatial recognition device 280 includes a front camera 280F attached to the front end of the upper surface of the upper rotating body 203, a rear camera 280B attached to the rear end of the upper surface of the upper rotating body 203, a left camera 280L attached to the left end of the upper surface of the upper rotating body 203, and a right camera 280R (not visible in FIG. 10) attached to the right end of the upper surface of the upper rotating body 203.

The spatial recognition device 280 is, for example, a monocular camera having an imaging element such as a CCD or CMOS, and outputs the captured image to the display device 40. The spatial recognition device 280 may also be configured to calculate the distance from the spatial recognition device 280 or the work machine 200 to the recognized object. In addition to using the captured image, when a millimeter wave radar, ultrasonic sensor, laser radar, or the like is used as the spatial recognition device 280, multiple signals (laser light, etc.) may be transmitted to the object, and the reflected signals may be received, from which the distance and direction of the object may be detected.

The spatial recognition device 280 is configured to detect objects present around the work machine 200. The objects are, for example, dump trucks, terrain features (slope, holes, etc.), electric wires, utility poles, people, animals, vehicles, construction machinery, buildings, walls, helmets, safety vests, work clothes, or specific marks on helmets. In this manner, the spatial recognition device 280 may be configured to identify at least one of the type, position, and shape of an object. For example, the spatial recognition device 280 may be configured to distinguish between people and non-human objects.

The boom cylinder 207 may be equipped with a boom rod pressure sensor S206a, a boom bottom pressure sensor S206b, and a boom cylinder stroke sensor S207. The arm cylinder 208 may be equipped with an arm rod pressure sensor S206c, an arm bottom pressure sensor S206d, and an arm cylinder stroke sensor S208. The lifting magnet cylinder 209 may be equipped with a lifting magnet rod pressure sensor S206e, a lifting magnet bottom pressure sensor S206f, and a lifting magnet cylinder stroke sensor S209.

The boom rod pressure sensor S206a detects the pressure in the rod side oil chamber of the boom cylinder 207 (hereinafter referred to as the "boom rod pressure"), and the boom bottom pressure sensor S206b detects the pressure in the bottom side oil chamber of the boom cylinder 207 (hereinafter referred to as the "boom bottom pressure"). The arm rod pressure sensor S206c detects the pressure in the rod side oil chamber of the arm cylinder 208 (hereinafter referred to as the "arm rod pressure"), and the arm bottom pressure sensor S206d detects the pressure in the bottom side oil chamber of the arm cylinder 208 (hereinafter referred to as the "arm bottom pressure"). The lifting magnet rod pressure sensor S206e detects the pressure in the rod side oil chamber of the lifting magnet cylinder 209 (hereinafter referred to as the "lifting magnet rod pressure"), and the lifting magnet bottom pressure sensor S206f detects the pressure in the bottom side oil chamber of the lifting magnet cylinder 209 (hereinafter referred to as the "lifting magnet bottom pressure").

The upper rotating body 203 is provided with a cabin 210 as a driver's cab and is equipped with a power source such as an engine 11.

A cabin 210 is provided on the upper rotating body 203 so that it can be raised and lowered via a cab lifting device 290. Hereinafter, such a cabin that can be raised and lowered may be referred to as an "elevator cab." Note that FIG. 1 shows the state in which the cabin 210 has been raised to its highest position by the cab lifting device 290. The cabin 210 is also located to the side of the boom 204 (usually on the left side).

The work machine 200 has a hydraulic drive system, including the engine 11, similar to that of the excavator 100 shown in FIG. 2, and so a detailed description will be omitted.

Compared to the excavator 100 of the above-described embodiment, the work machine 200 of this embodiment is equipped with a lifting magnet 206 instead of a bucket 6 on the work tool at the tip of the attachment. Therefore, the controller 230 of this embodiment differs from the controller 30 of the above-described embodiment in that it performs control corresponding to the lifting magnet 206.

The controller 230 according to this embodiment controls the transported object attracted to the lifting magnet 206 so that it is loaded onto a dump truck. If the transported object attracted to the lifting magnet 206 falls during transport to the dump truck after its weight is measured, a measurement error will occur. Therefore, the controller 230 according to this embodiment measures the weight of the transported object attracted to the lifting magnet 206 multiple times. Then, when the controller 230 determines that a deviation from the previous measurement result has occurred, it performs control to respond to the drop of the transported object.

As a control to deal with the falling of the transported object, for example, the boom 204 is lowered so that the fallen transported object is attracted to the lifting magnet 206 again, or the magnetic force output of the lifting magnet 206 is increased so that the fallen transported object is attracted to the lifting magnet 206 again. Furthermore, a warning may be displayed as in the above-mentioned embodiment.

Figure 11 is a flow chart showing the processing procedure up to loading a load onto a dump truck DT by the work machine 200 according to this embodiment. The example shown in Figure 11 shows the processing after the work machine 200 has completed the suction operation of scrap materials or the like (hereinafter referred to as the load) and the lifting magnet 206 has completed suction of the load.

In the present embodiment, the controller 230 performs the process of loading the load onto the dump truck DT by calculating the weight of the load twice in the same manner as the process shown in FIG. 9, and then the weight determination unit 62 performs the process of determining whether or not |First detection value - Second detection value| < the determination threshold is satisfied (S901 to S907).

If the weight determination unit 62 determines that the condition is met (the load has not fallen) (S907: Yes), the weight determination unit 62 provisionally determines the first detection value as the actual weight of the load (S908).

On the other hand, if the weight determination unit 62 determines that the condition is not satisfied (part of the load has fallen) (S907: No), the automatic control unit 54 performs re-adsorption control for the fallen load (S1101). The re-adsorption control may be performed by any method. For example, the automatic control unit 54 may lower the boom 4 to re-adsorb the fallen load.

Furthermore, because part of the load has fallen, there is a possibility that some of the loads attracted to the lifting magnet 206 are likely to fall. Therefore, the automatic control unit 54 may re-attach the loads attracted to the lifting magnet 206. For example, the automatic control unit 54 controls the lifting magnet 206 to strengthen its magnetic force by adjusting the power flowing through the lifting magnet 206. This strengthens the attraction force for the loads that are likely to fall, thereby preventing the loads from falling any further.

Then, the load weight calculation unit 61 recalculates the weight of the load currently attached to the lifting magnet 206 and provisionally determines the calculated weight as the actual weight (S1102). This process makes it possible to properly detect the weight of the load attached to the lifting magnet 206, regardless of whether the load has been reattached.

After that, when the controller 30 determines that the load attracted to the lifting magnet 206 has been discharged onto the bed of the dump truck DT by the operator's operation, the weight determination unit 62 confirms the provisionally confirmed weight of the load (S911).

Then, the added load calculation unit 64 accumulates the weight of the load loaded on the dump truck DT (S912). Furthermore, the remaining load calculation unit 65 calculates the difference between the maximum load of the dump truck DT and the current added load calculated by the added load calculation unit 64 as the remaining load.

The above-described processing procedure allows control to be performed in the event that part of the load attracted to the lifting magnet 206 falls. This makes it possible to prevent the load (scrap parts, etc.) from falling onto the surroundings of the work machine 200.

In the above-described processing procedure, an example has been described in which the weight of the load is detected twice while the boom 204 is being raised. However, this embodiment is not limited to the method of detecting the weight of the load twice while the boom 204 is being raised, and the load weight calculation unit 61 may detect the weight of the load while the upper rotating body 3 is performing a rotating operation after detecting the weight of the load while the boom 204 is being raised. Even in this case, if the weight determination unit 62 determines that part of the load has fallen, the load may be re-adsorbed using a procedure similar to the above-described processing.

Furthermore, the load weight calculation unit 61 may detect the weight of the load twice while the upper rotating body 3 is rotating. Even in this case, if the weight determination unit 62 determines that part of the load has fallen, the load may be re-adsorbed in the same manner as in the above-mentioned process.

In the above-mentioned process, an example in which the automatic control unit 54 performs re-adsorption control has been described. However, the present invention is not limited to a method in which the automatic control unit 54 performs re-adsorption control. For example, when it is determined that the load has fallen, the information transmission unit 53 may display on the display device 40 that the operator has fallen and that the operator is prompted to re-adsorb the load.

In this embodiment, by improving the accuracy of calculation of the weight of the load by the controller 230, the rework of weighing adjustment can be reduced, thereby improving the work efficiency at the loading site. Furthermore, when a load that was attracted to the lifting magnet 206 falls, the controller 230 according to this embodiment re-attracts the fallen load, thereby preventing the fallen load from scattering around the work machine 200.

(Modification of the third embodiment)
In the above-mentioned third embodiment, an aspect in which the weight of the load attracted to the lifting magnet 206 is detected multiple times has been described. However, the method of detecting the weight multiple times is not limited to the method shown in the third embodiment. Therefore, in a modification of the third embodiment, an example in which the load weight calculation unit 61 repeatedly detects the weight in accordance with the calculation cycle of the controller 230 will be described. In this modification, it is considered that the weight detection is repeated, for example, every 0.1 seconds.

Then, the weight determination unit 62 judges whether or not |previous detection value - current detection value| is greater than the judgment threshold. If the weight determination unit 62 judges that |previous detection value - current detection value| is greater than the judgment threshold, it assumes that the load has fallen, and the automatic control unit 54 performs re-attachment control of the load. The re-attachment control in this modified example involves adjusting the power flowing through the lifting magnet 206 to strengthen the magnetic force of the lifting magnet 206.

In this modified example, when it is determined that the load has fallen (in other words, the moment the load falls from the lifting magnet 206), the automatic control unit 54 controls the lifting magnet 206 to strengthen its magnetic force, so that the load in the middle of falling can be attracted to the lifting magnet 206 again.

In addition, this modified example does not limit the re-adsorption control to control that strengthens the magnetic force of the lifting magnet 206. When the automatic control unit 54 determines that the load has fallen (in other words, the moment the load falls from the lifting magnet 206), it may perform control to lower the boom 204 and cause the load that is falling to be attracted to the lifting magnet 206 again.

In addition, in this modified example, after performing re-adsorption control, the load weight calculation unit 61 detects the weight of the load adsorbed to the lifting magnet 206. Thereafter, the load weight calculation unit 61 again performs weight re-detection repeatedly in accordance with the calculation cycle of the controller 230. If it is determined in the weight detection that the load has fallen, re-adsorption control is performed to prevent the load from falling. Furthermore, by re-detecting the weight, it is possible to detect the weight with high accuracy. Therefore, similar to the third embodiment, it is possible to prevent the fallen load from scattering around the work machine 200.

In the above-described embodiment and modified example, the accuracy of calculation of the weight of the load by the controller 30 is improved, thereby reducing the need for rework to adjust the weight, and thus improving work efficiency at the loading site. In addition, the controller 30 according to the above-described embodiment can load the load up to near the upper limit of the load that the dump truck can carry, thereby improving transport efficiency. Furthermore, the controller 30 according to the above-described embodiment can prevent the dump truck from being overloaded with the load, thereby reducing damage to roads caused by the load of an overload.

Although the embodiment of the work machine according to the present invention has been described above, the present invention is not limited to the above embodiment. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. Naturally, these also fall within the technical scope of the present invention.

100 Excavator 200 Work machine 1, 201 Lower traveling body 2, 202 Swing mechanism 3, 203 Upper rotating body 4, 204 Boom (attachment)
5, 205 Arm (attachment)
6. Bucket (work tool)
206 Lifting magnet 7, 207 Boom cylinder 8, 208 Arm cylinder 9 Bucket cylinder 209 Lifting magnet cylinder 30, 230 Controller 50 Machine guidance section 51 Position calculation section 52 Distance calculation section 53 Information transmission section 54 Automatic control section 55 Swing angle calculation section 56 Relative angle calculation section 60 Weight processing section 61 Load weight calculation section 62 Weight determination section 63 Maximum load amount detection section 64 Added load amount calculation section 65 Remaining load amount calculation section 66 Load center of gravity calculation section

Claims (9)

A lower running body;
An upper rotating body rotatably mounted on the lower traveling body;
An attachment attached to the upper rotating body;
A working tool provided at the tip of the attachment,
measuring the weight of the load twice at different positions while the load is being transported by the working tool, and if the difference between the weights measured twice is equal to or greater than a predetermined value, performing a predetermined control to prevent the load from falling.
Working machinery. As the predetermined control, the latter of the two weight measurements is adopted as the measured value.
2. The work machine of claim 1. measuring the weight of the load twice at different positions, and if the difference between the two weight measurements is smaller than the predetermined value, adopting the earlier of the two weight measurements as the measured value.
3. A work machine according to claim 2. determining the taken measurement based on movement of the work implement after the measurement has been taken;
3. A work machine according to claim 2. As the two measurements, a first measurement of the weight of the load is performed while a boom included in the attachment is being raised, and a second measurement of the weight of the load is performed after the boom is raised and after the upper rotating body starts to rotate.
2. The work machine of claim 1. As the two measurements, a first measurement is performed on the weight of the load, a boom included in the attachment is raised after the first measurement, and a second measurement is performed on the weight of the load after the boom is raised.
2. The work machine of claim 1. When the latter of the two weight measurements is adopted as the measured value, information is output to an operator of the work machine, indicating that a part of the load has fallen from the work implement.
2. The work machine of claim 1. The working tool is a lifting magnet capable of attracting the load,
When the difference between the weights measured twice while the load attracted to the lifting magnet is being transported is equal to or greater than the predetermined value, the predetermined control is performed to re-attract the load that has left the lifting magnet.
2. The work machine of claim 1. When re-attaching the load that has left the lifting magnet, a control is performed to strengthen the magnetic force generated by the lifting magnet compared to before the difference between the weights measured twice becomes equal to or greater than the predetermined value.
9. A work machine according to claim 8.

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